


Professor Black

by Haunted_Frost



Category: Harry Potter - J. K. Rowling
Genre: Alternate Universe - Canon Divergence, Animagus, Azkaban, Black Family (Harry Potter) - Freeform, Book 1: Harry Potter and the Philosopher's Stone, Book 2: Harry Potter and the Chamber of Secrets, Book 3: Harry Potter and the Prisoner of Azkaban, Brother Feels, Drinking, Family Feels, Gen, Other Additional Tags to Be Added, Regulus Black Lives, Smoking, Video Game: Harry Potter: Hogwarts Mystery, Work In Progress
Language: English
Status: In-Progress
Published: 2019-02-18
Updated: 2019-10-08
Packaged: 2019-10-30 18:52:51
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 10
Words: 24,878
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17834201
Author URL: https://archiveofourown.org/users/Haunted_Frost/pseuds/Haunted_Frost
Summary: Kreacher's unending loyalty has allowed Regulus to survive the Inferi.  In order to destroy the horcrux and ensure Voldemort's death, he goes back to Hogwarts, this time as a Potions professor.  Years at this position give him new insights, even as the papers rave about how both the Blacks were traitors to their sides.When Sirius gets loose from Azkaban, Regulus knows one thing: he is not going to let his lunatic brother hurt his students.Inspired entirely bythis tumblr post.





	1. Directed Ferocity

**Author's Note:**

> Okay, this is my second Regulus Lives fic because I live for the Black brothers reuniting and such. I tried really hard to line up timelines correctly, though I'm throwing most of the plot of Hogwarts Mystery out the window because a) it's unfinished and b) I'm stealing the characters, not the plotlines, because this fic is about Reg.
> 
> Not sure as of original posting, but I think this will be 3-5 chapters, depending on what I do with it. General idea atm is to end it at Prisoner of Azkaban, because that's what we're all here for, but I may do an epilogue after we get there.

He was delirious and in pain for all the hours that he was aware.  He didn’t know what was going on, couldn’t open his eyes. 

For a while, he thought— _ah, so a last heroic act wasn’t good enough to get me out of hell?_

But he saw flashes of his room, of Kreacher leaning over him.  It was just enough to make him wonder.  _The poor old thing—he probably is beating himself over this_ —he wished he could speak.  _So thirsty._   So weak.  He couldn’t even tense up.  Everything was so heavy. 

He slept.  Pain whirled through him.  He never quite dreamt, but the Inferi were always behind his eyelids. 

Eventually, though, he woke a little more.  Bit by bit.  It was beyond slow.  Water cooled his throat.  Blankets.  Twitches in his muscle.  The smell— _Merlin, I need a bath._  

Once he’s awake enough, once he can open his eyes and actually see, he blinked around.  His bedroom.  The horcrux sitting at the foot of his bed.  Kreacher was passed out on the floor; he must have worn himself out over a beating.  Regulus grimaced.  Everything felt like it had when he’d been under that blasted aging potion Potter had slipped into his drinks in fourth year. 

He shifted himself around for what must have been a few minutes—movement that used to take seconds.  _Are my joints grinding together?_

He grumbles.  Stands.  Nearly falls over. 

“Kr-chr,” he rasped.  The elf twitches.  Rises. 

“Master Regulus?” his old servant asked. 

* * *

Recovery for the both of them was slow-going.  But Kreacher bounced back first, and it was quicker work when Regulus ordered him not to punish himself for disobeying in between treating and feeding his master.  The next important thing was news: what had happened since he’d gone on his suicide mission?

The dark lord dead—the Potters dead—Sirius, a traitor. 

Regulus wanted to laugh—the two of them, both traitors.  No one would have guessed.  What a riot.  He cried instead, in hysterics because _dammit Sirius you were supposed to be the good one_ and his big brother was as good as dead in Azkaban. 

And the Dark Lord wasn’t—would never really be dead as long as the horcrux is around.  And Regulus would not trust absolutely anyone with this secret, doesn’t want another Voldemort to rise if the idea ever went public.  Immortality at the price of murder?  People killed for less. 

He’d killed for less.

He wanted to scream that he was just a kid, wanted to blow up the whole house some days, just to see it burn.  But he couldn’t stop, could he?  He had to destroy the horcrux.  He had to keep living and doing the right thing. 

He waited a few months more, until it was the end of the school term, before placing the Floo call. 

“Headmaster,” he said, and for all he was too young, he knew what he was going to do.  “I’d like to apply for a position at Hogwarts.  Can we set up a meeting time?”

* * *

Naturally there were interrogations, Veritaserum, but he was always careful all the same.  He never lied the whole way through, telling them how he defected, how he stole some important artifact Voldemort was hiding and such, meaning to die trying to destroy it.  He said enough to tentatively be trusted, enough that he wondered how many “loyal” death eaters pretended to defect to protect themselves.  He didn’t need to think too hard about who had the money to get through it without issue.  Cissy sent him a letter, as did Andromeda.  They certainly knew what buttons to push. 

_Dear Regulus,_

_It’s good to know that you made it out, in the end. A shame that we both lost siblings to that hopeless cause.  Lucius was incredibly frightened throughout the whole ordeal, though he’d never say so.  I’m quite satisfied that I never took the mark—best not to show loyalties I don’t have.  We are Blacks, after all.  My son, Draco, could do with a better man in his life than his godfather; Severus was Lucius’s first choice, as I’m sure you remember, and I hardly want my son skulking about like that man.  He could do with more family.  Please come to tea sometime._

_Best,_

_Narcissa_

Regulus frowned.  Lucius and Severus both free?  And Narcissa’s son—oh he was going to be a little bastard when he grew up, if Reg had any guesses to make about Lucius’s attempts at parenting.  And he was quite sure that Narcissa wasn’t asking about tea—she was demanding. 

He’d have to see if he could clean up for that visit.  Andromeda’s letter was a bit longer. 

_Dear Reg,_

_Oh, you’ve been through the thick of it, haven’t you?  It’s all dreadful, it is, seeing the aftermath of those horrors You-Know-Who committed.  I hope what they say is true, that you defected yourself, and that you’re not just saving face. That’s something Lucius would do, that Cissy would cop to, but I was never sure with you.  Do you want to come over sometime?  Ted doesn’t have much family, and now, well, neither do I.  I’m sure Dora—our daughter, oh, she’s lovely, a little spitfire—would love meeting her cousin._

_I’m glad you’re alive, Reg.  Rumors say it was a near thing.  I’d say I can’t believe it with Bella—but I’d be lying.  It’s sad enough that I saw her coming, but Sirius blindsided me.  I never thought he’d be capable of what he did—well, unless he had good reason.  But what good reason do you have for betraying your best friends, for killing twelve people?  For killing a friend?  I know he’s got a temper, but . . . I don’t know.  It’s all terrible, even with You-Know gone.  I just.  I miss them.  And I miss you.  Come over sometime?  I hope you are doing well all the same._

_With Love,_

_Andy_

They were so similar he was going to scream. 

_Andy,_

_I’m fixing up Grimmauld for myself to live in—I’m rather sick of Mother’s portrait screaming that I’m a traitor, so I’m combing through the place.  It may be some time before I can come over, but I’ll write often in the meantime._

_Best,_

_Regulus._

He wrote the same, but with “Cissy” for Narcissa, and sent the owls off. 

* * *

The next morning, he got an enthusiastic bang at his door.  Andy and Ted, Dora in tow, had arrived. 

“I’m sure we can handle the old hag,” she said brightly.  “Much more fun if she splits the yelling between the two of us.”

Nymphadora, grinning, nodded.  She was eight or so, if he remembered correctly. 

“Can’t have a hag!”

“You’re right, miss Dora,” he nodded seriously.  He turned and led them to a parlor. 

“Haven’t made much progress quite yet,” he admitted.  “Lots to do.  I apologize for anything cursed or particularly nasty dust bunnies.”  Another sharp knock at the door. 

“I’ll get it,” Regulus said, and he was honestly surprised to see Narcissa with a little blonde baby tucked in her arms. 

“Uh.”  Regulus blinked.  “Hi, Cissy.  I already have company—”

“Cissy?” Andromeda asked, coming down the hall. 

* * *

They had their tea anyway, Dora playing with baby Draco on the carpet. 

“Well, the charm has her pretty solidly stuck there,” frowned Andy. Mother screamed about traitors to their name. _Charming_.  

“Not if we cut away the wall.”  Regulus blinked at Narcissa’s smirk.  He’d seen that face a thousand times on Sirius.  

“I like that idea,” grinned Ted.  “It shouldn’t be too hard, either.  A little Muggle application, then a little magic mending, good as new.”  Narcissa’s face pinched, but she didn’t say anything.  Regulus frowned.  Surely there was a magical way to go about it—but Ted had already grabbed a tool set and started punching holes in the wall.  Andy just grinned. 

* * *

Unfortunately, the house didn’t hold anything that could destroy the horcrux.  And Regulus doubted anyone would just lend him horcrux research.  The only thing left was—

Hogwarts.  It had an extensive library, not to mention ways to research from other libraries.  He wasn’t a student anymore, but he’d always wanted to teach at Beaubaxtons—No, Hogwarts would serve him better in this case.  It’d be a hell of a time trying to apply, though, given his limited work history as a death eater turncoat.  He was only 20, but he had enough experience.  Defense Against the Dark Arts, maybe, since that position was always open, or Potions, since Slughorn was retiring. 

Unfortunately, he had competition.  Fortunately, their expertise was about the same. 

“Severus,” he said blandly, eyeing him as the older man exited Dumbledore’s office. 

“Black.  Good to see you,” he said.

“And you as well.”  And passed into the office. 

“Ah, Regulus, how wonderful,” the old man smiled.  “Please, sit.  Make yourself comfortable.”  Regulus sat stiffly in the chair. 

“I don’t suppose I have much of a chance, then,” he said, “Our credentials are the same, but he’s older and has recommendations from Slughorn, yes?”

“And you’re younger, and you have more variety in your skills.  I hesitate on the position of Defense, because of the nature of the position.  But Potions?  You’re both evenly matched.  Severus and I have a . . . separate arrangement, as well.”  Regulus sighed. 

“I will be frank, Dumbledore.  I do want to teach—that’s all I’ve really wanted to do—but I’m applying here instead of Beaubaxtons for graver reasons than convenience.  Tell me; do you truly believe the Dark Lord is dead?  Because I have reasons to believe he isn’t.”  Albus smiled. 

“And I was just asking Severus the same question.  Well, my good man, what do you think?”

“I think it’s darker magic than most people know of,” Regulus said slowly, “And frankly, I think it best that no one ever knows of it again.  It’s a terrible thing, soul-rending, even.”  If Dumbledore knew what a Horcrux was already, he didn’t show it.  He nodded. 

“Indeed.  What Voldemort did was quite beyond regular evil.  It was certainly something I hadn’t seen before.  And, should he come back, where will you be, young man?”

“Fighting tooth and nail to kill him, if he can be made mortal.”  The old man seemed to have his answer. 

“That’s nearly what Sirius said when I asked him to join the Order,” he said.  Regulus snarled. 

“Is that an accusation?”

“Oh, no, commendation.  Ferocity like that is commendable, Regulus, when it’s directed on the right path.”

He thought of Sirius’s snarling mugshot, of Bella’s vicious screeches and giggles and _avada kedavra_ s.  Ferocity.  Right.

* * *

He got the job.  He didn’t know yet whether that was a good thing.  His entire first year was full of glares and snide comments from students and staff alike.  He said nothing for the first while—after all, the war was still a fresh wound—but Halloween came around and he was _done_ with being questioned about whether he would teach the Unforgiveables in his spare time. 

“I am _not_ going to snap and hurt someone!” he growled lowly, dropping his head to his hands as he graded essays.  “Bloody—”

“Professor?” a small voice asked, and he sat up.  Oh, Merlin, a first-year had just heard him curse.  Well.  At least he hadn’t pulled out the wine yet. 

“Yes, Mister Weasley?” he asked.  The kid frowned. 

“You seem busy—maybe another ti—” 

“No, no,” Regulus shook his head.  “I’m frustrated with some things, but I’m still your teacher.  What do you need, Bill?” 

He shifted around awkwardly. 

“One of my housemates . . . was making comments.  About my family.”  His chest puffed up a little.  “I’m the oldest of seven now.  It takes a lot to take care of all of us.  So we don’t always have the best stuff.  And he always makes jokes about it during Potions, so I want to switch partners.”  Regulus raised an eyebrow. 

“That’s Mr. Frey, right?  I’ll see to it that he’s reassigned.  May I ask how long this has been going on?”

“Since the first week.”

“How come I haven’t caught him?” 

“He waits until you’re on the other end of the room, since Alyssa always needs help there.”  Regulus hummed. 

“Would you indulge me in one half of a class with him?  I would like to catch him in the act so no one accuses me of targeting young Gryffindor students.”  Bill frowned. 

“They’ve been doing that?  But you’re really fair.”  Regulus laughed. 

“Try telling everyone else that.  They think I’ll start throwing Dark curses if someone so much as gives me an inch of opportunity.  I just want to teach.”  He squared his shoulders, the little redhead, face determined and eyes steely. 

“I’ll tell them that.” 

* * *

Oh yes, the next class he listened carefully even as he helped young miss Harrows understand the measurements—numbers were not her strong suit.  He had to strain his hearing and focus a bit to hear one voice through the murmurs, but—

“D’you think your little brothers’ll start having to be homeschooled?  Which ones are going to teach which?  Will you be Professor Binns, your dad Dumbledore?  ‘Detention, go clean your room,’ he’d say.  Would you get kicked out if you get expelled?” the kid chuckled. 

“Mr. Frey,” Regulus said sharply.  “Would you like to stand up and share with the class what you just said?  It sounds riveting.”  The boy’s face went red. 

“No?  Well, if it isn’t all that amusing, maybe you should think twice before you speak.  I won’t take points, because it was your own House member you were bullying, but if I ever hear it again, I’m going to have a word with Professor McGonagall.  Weasley, switch with Cobble, if you wouldn’t mind.  Back to work, everyone.”  And Bill beamed up at him. 

Maybe it was worth it. 

* * *

“Regulus,” McGonagall called across the corridor.  “A word?”

Maybe it wasn’t worth it. 

“Yes, Minerva?” 

“I heard about the incidents with Mr. Weasley and Mr. Frey.  Thank you for intervening.  I had no idea.”

“Neither did I, until Bill came to my office.” 

“Yes,” she pursed her lips, a tiny smile.  “And Mr. Weasley was adamant that you were ‘very fair, a good teacher’ and ‘so cool’.  He’s been saying it in every class since he left potions.”  Regulus felt his face heat up. 

“I didn’t think he’d actually—I was being sarcastic, Merlin, I’ll talk to him—”

“No, no, Regulus.  I think he’s doing a good thing here.  I know I was cold when you came in, but.  Well.  He reminded me of when you first came to Hogwarts.  It was charming.  I won’t tell him that, of course, he’ll never pay attention—” And Regulus laughed. 

“Best thing I’ve heard all week.”

* * *

From then on, the teachers seemed to back off, at least enough that they weren’t outright antagonistic.  Wizarding family kids, however, were a bit harder sometimes. 

Either they were on the Light and thought of him as a Death Eater, or they were with the Dark and saw him as a traitor.  But it got better every year, and the kids that came in expecting the worst from him never thought the same before they left. 

His research was at least going better than it had at home.  But with being responsible for multiple classes of Potions for multiple years, he couldn’t exactly make a lot of headway.  Not to mention as a new professor, he was still somewhat restricted from the Restricted Section.  Unless he snuck in, this was going to be an issue. 

He came on the idea rather quickly, though—animals could go as they pleased.  And he could listen in on others more easily.  Maybe he could figure out _what the hell_ Dumbledore knew about horcruxes that he wasn’t letting on, or why he’d chosen Regulus over Snape. 

Overall, it wasn’t a bad venture to go after.  He sent letters to McGonagall as he studied, asking about the precision required and what parts of the spell were the most difficult in her position. 

Timing, it seemed, was the worst of it—dew that had not been touched for seven days, a lightning storm, full moon cycles, all of it had to be perfectly timed.  No, he would not be doing this during the school year.

It was ever-clearer that he would do it though, as nothing in his research was _helpful_.  Something about a horcrux needing to be completely destroyed, killed—he found in one book in the Restricted Section that the piece of soul also provided its own protections.  But the year passed the same as before, and he still didn’t have answers.  Minerva, at least, was more than happy to help him become an animagus, and he stayed for some time over the summer to work with her on the potion and spellwork before getting registered. 

The first transformation left him blinking, but Minerva looked down at him, pleased. 

“A Norwegian Forest Cat,” she murmured.  Ah, well.  He’d been hoping for something that could fly, but he’d take what he could get.  When he finally transformed in front of a mirror, he snorted—as close as he could get to a laugh as a cat.  Really.  A Black cat.  A black cat. 


	2. (All Around Me) Familiar Faces

**Summary for the Chapter:**

> The years of Hogwarts Mystery are beginning. Regulus has an entirely different mystery to solve, however: will he be able to figure out how to destroy a horcrux?

Being an Animagus was all well and good—he amused himself quite easily in between picking through older documents on eternal life.  The Elixir of Life might have been a route Voldemort went after . . . But the next year of teaching was not going to be easy, because Dora was coming to school, and Andy was going to _give him shit_. 

“Do we need to hold parent-teacher meetings?” she asked with an utterly straight face while they ate at the Leaky Cauldron. 

“Only if I have to with Cissy when Draco comes to school.”

“Excellent,” she grinned.  “If Dora sends me any owls alerting me to the fact that you’re actually dismal, I’ll let you know.  She won’t say it to your face, after all.”

“Now _that’s_ a lie.”

* * *

 “Watch out for Hera Mayne,” whispered the Bloody Baron.  “Her brother, Jacob, was right trouble.  Got his wand snapped and everything, they say, after what he did.” 

“I’m more concerned about my cousin,” Regulus replied.  “She will make fun of me in front of my students.  She will undermine me.  I should have ignored Andy’s letter from the start.”

He peered at the students lining up for sorting.  Like any year, they were all nervous, skittering about, even the purebloods that knew all about it.  He remembered his own sorting well, and he glanced at his new Slytherin first years—he recognized Snyde, Lee, and Murk vaguely.  Tuttle was a Muggleborn, probably, and Mayne—well.  He hadn’t known Jacob Mayne personally, but if the Baron was concerned, then he supposed he ought to keep an eye out. 

And then Dora.  He didn’t expect Slytherin, really—in fact, he suspected she might be a Gryffindor.  So he was altogether flabbergasted when the Hat immediately shouted:

“HUFFLEPUFF!” and she smirked like that’s what she wanted and sauntered off to the students in yellow.  Bill’s younger brother got Gryffindor, which was good to know—he wouldn’t be alone with unfamiliar faces at all, which he probably needed after growing up in such a large family. 

. . .

“Welcome to the Slytherin common room,” Regulus gestured about.  “I’m Professor Black, and I am your head of house.  Your prefects here will act in my stead when I am not here—they will be your guides, your mentors.  They will dole out points and take them away, same as any teacher, though they have limits, and they, too, can alert me if they feel you need detention.  This is school, but it is also your home.  Your house mates are about to be your family for the next seven years.  We have the unfortunate privilege of being known as evil and conniving to all the other houses.”  He paused. 

“But such is the same for the others—Gryffindors are brash idiots, Hufflepuffs are boring sticks in the mud, and Ravenclaws are uptight bookworms.  You’ll find this all to be absolutely true in some cases, and a lie in others.  Evil can come from our house, but so can greatness, and I expect you all to do more than I did with my schooling.”  His left arm itched. 

“That is, I expect you all to do great things.  I know you can.  Now, Prefects, assist your first years with unpacking and finding everything.  Once everyone is settled, call lights out.  I’ll see you all in class.”

* * *

First year potions taught him patience—it always did, going through safety parameters again and again and _again_ as students learned precisely why there were parameters in the first place.  Having Gryffindor and Slytherin together usually meant that it took quite a bit longer to hammer it into their brains to follow directions. 

“You idiot,” he heard Merula Snyde hiss to one of the others at her table.  “You’re so _slow._ ”  We have to get this done by the end of class, and there you are, sitting around.”

Ugh, children were terrible sometimes.  He turned around to ask her to be quiet when her other potions partner, Hera, leapt from her seat. 

“I’ve had enough of you acting like you’re better than the rest of us!  We’re all first years and we all have the exact.  Same.  Directions.  We’re literally just starting, all of us!  You don’t know any more than he or I do, so stop acting like you do!” 

“Miss Mayne, Miss Snyde.  Ten points each from Slytherin for disrupting class.”  They both shut up, glaring at one another as they chopped herbs in silence.  Charlie seemed to be having a grand old time with Barnaby, though, as they chatted away about Quidditch and dragons quietly. 

“Can I see your Dark Mark?” asked Ismelda after class. 

“No.  Head along, Ms. Murk,” he sighed.  This was going to be a long year. 

* * *

“ _Professor_ ,” Dora grinned. 

“Nymphadora,” he replied.  She made a face. 

“Ew.  Ugh.  Call me Tonks if you must, but not that.”  He grinned. 

“It’s a Black tradition, _Nymphadora._   But if you insist.”  She shuddered and glared at his second mention of her full name.  She didn’t mess with him once throughout the rest of class.  She even helped Ms. Ali figure out a part of the instructions she didn’t understand—really, five points to Hufflepuff were justified; it wasn’t favoritism. 

* * *

“ _Tantellegra!”_ cried a familiar voice as he made his nighttime rounds.  He shook his head as he turned the corner—Mayne and Snyde, doing their best to duel one another. 

“That’s quite enough.  Wands, down.  Detention, both of you.  My office.  _Now._ ”

* * *

Mayne and Snyde were nightmares when they were together, though Mayne was decent enough on her own.  Merula clearly needed some reality checks, though. 

No, his favorite first year class was the Hufflepuff-Ravenclaw one, not because of Dora, but because of young Penny Haywood, an absolute delight in the class.  And he meant that word from the bottom of his heart.  She hung onto every direction, helped students around her that were struggling, and asked meaningful questions every chance she could. 

* * *

Unfortunately, throughout the year once holidays had passed, there was an awful strain of Devil’s Snare sneaking about the castle.  A student that was studying it, perhaps, dropped seedlings all over, and they’d run rampant and take hold of any unsuspecting student. 

Or someone was thinking they’d played a viciously wonderful prank.  Whatever the case, Sprout was all about the castle trying to clean up the mess without killing it. 

Mayne was casting strong Lumos spells right up against the things, which had Khanna, a major bookworm, trapped for hours. 

“Twenty points to Slytherin for finding a way to free Rowan without killing the plant.  Fire would have been quite problematic and unwieldy, no?”

Hera grinned. 

* * *

Hufflepuff was the house to win that year, and Dora gloated as soon as he’d walked in the door.  He snorted; clearly giving Andy and Cissy open permission to visit was a mistake. 

“I think this summer I’m going to tackle the old Black estate in Normandy,” he said, “Or at least the library.  Fancy a trip to France for June and July?  I’ll invite Cissy, too.”  Andy’s face pinched. 

“Could we ban Lucius?”

“No, unfortunately.  Not unless you want to ban Ted, too.” 

“Black family trip!” cheered Tonks. 

And that was that. 

* * *

The Black archived library was informative to say the least. While a large portion of the library was filled with books on their lineage—important events, bloodlines, marriages—the books available were valuable. 

“What do we do with these?” wondered Narcissa.  “All that history—”

“Frankly I’m itching to toss them, but I know that wouldn’t fly,” Andy shrugged.  Narcissa stiffened. 

“You’d throw away all of that?”

“Or sell it, or _something_ —it’s not stuff we really need to keep categorized like it is.  Or maybe a more hidden archive, even—”

“Malfoy Manor has good hiding places,” Narcissa said coolly.  “I’ll take them.”

“By all means,” Regulus waved. 

It hadn’t been a complete waste of time, though.  One book mentioned horcruxes in passing—that they were vessels for pieces of a person’s soul. 

It wasn’t much, but it did give him a genre of magic to focus on.  Not hexes, not charms, not transfiguration, not curses—no, this was a dark ritual he was dealing with. He just had to figure out how to break it. 

**Notes for the Chapter:**

> Yeah, sorry for the short chapter. The information on the HPHG years is probably going to be slimmer, so the coming years may be paired up within chapters once I get around to them. School is being a major pain but I figured you'd like a bit of an update!
> 
> I am pretending there's no such thing as R, the Cabal, or the Cursed Vaults whatsoever for this fic because A) that would just be a bad retelling of the game with Reg instead of Snape, B) the game's plot hasn't finished and I'm not going to wait on that to write Sorcerer's Stone plot stuff and C) I really just want to play with the characters, and Reg's more important than the students in this case, so it would be pointless to try to redirect it anyway. 
> 
> Originally I was going to have a male Ravenclaw MC named Hiro Mayne, but I figured what the heck. I decided on female MC and stepped away from Ravenclaw because that way there'd be more reason for Reg to get involved. 
> 
> As always, comments are super appreciated!


	3. How Many Horcruxes Can a Dark Lord Make?

**Summary for the Chapter:**

> Hogwarts Mystery Years 2 and 3, where Regulus deals with all sorts of student issues, along with one particular new step in figuring out the Horcrux Problem. 
> 
> Merlin, am I turning into Sirius? he thought before remembered. 
> 
> No. I’m being better than Sirius.

The continuing contraband Filch was finding was staggering, and there was no way that every student could have found all of those prank candies separately before even making it to Hogsmeade.  This year had been full of trips to the Hospital Wing, apparently due to some curse in the woods.  Regulus had to chase down student after student affected, and Madame Pomfrey was bogged down constantly trying to keep the students warm. 

So.  Many.  Pepper up.  Potions. 

He was also surprised to find that of all people to solve the problem, it had been Bill and some of the younger students—Ben Copper, who he hardly expected, and some muggleborn Gryffindors.  How did the _muggleborns_ figure it out before the professors? 

He hesitated to voice it, truly.  Ben Copper was _hardly_ an impressive member of that little group. 

But he said it quietly. 

“I’m surprised he was able to recognize the source of the curse,” he said quietly to McGonagall. 

“Mr. Copper is a paranoid young man,” she said, “I’d imagine he has quite the eye for danger, Regulus.  I don’t find it surprising at all.  He is very good at identifying threats in Defense, I hear.”

Could that be it?  An eye for danger?  He really needed to start paying attention to these children.

* * *

“Mudblood twit!” a kid hissed.  Regulus straightened.  He was the only professor that witnessed it.  He glanced at where the issue was happening—Ben Copper and an older Slytherin student. 

“What seems to be the problem?” he asked, stalking towards them.  Copper’s books were across the floor. 

“He shoved me,” said the elder student, a friend of Miss Murk’s, if he remembered correctly.  But more importantly, the younger cousin of a Death Eater he knew.  And this kid would remember that kind of thing.    

Mister Copper, on the other hand, was dazed and fearful.  _Quite the eye for danger, mm?_

“Mr. Rosier,” he said.  “50 points from Slytherin for making fun of a younger student, using a slur, and then lying about it.”  Rosier’s eyes widened.  But not as much as Ben’s.  _Merlin, am I turning into Sirius?_ he thought before remembered. 

 _No.  I’m being_ better _than Sirius._

* * *

Voldemort made multiple horcruxes. 

Regulus had been dreading the idea, because that made his search even harder.  But he couldn’t deny the protectiveness over little artifacts that the Dark Lord had passed on to different families.  Handing Bellatrix a cup, Lucius a book—but how many? 

How long was this going to be?

Dumbledore never gave any hints, and Regulus never let him know he knew, because then he’d be made into some sort of puppet-spy-retriever, and he wasn’t about to do that for anyone. 

* * *

The next year saw Bill taking his OWLs with his class.  Dora joked with Charlie that they could sneak the potions answers right to him. 

“Oh, come on, Professor Uncle,” she singsonged before cackling.  “Uncle Professor?  Profuncle?” He took a steeling breath. 

“Not a chance.  You’ll be in detention with Jae Kim in the kitchens for the rest of the year if you even think about it, Tonks.”

She shrugged and ambled away with her friends. 

* * *

One week, the Defense professor went down with a bad cold, and Regulus was asked to step in for a boggart class for the third years.  Because it interfered with some of his potions times, they combined more classes than usual. 

“All right, now, line up, we’re going to do this.”  It was better to do it at a younger age, because the fears were often less dangerously traumatizing.  A good bolster for them, to know that things can be conquered, which was why he definitely wasn’t going to face the thing coming out of the cupboard. 

“RIDIKULUS!” a giant wasp hit with a flyswatter. 

“Ridikulus!” a skeleton starting to tap dance.  Hera stepped up, and her brother was a ghost, accusing, glaring. 

“Ridikulus!” and it was Peeves instead, doing cartwheels. 

Copper fumbled, staring up at a red-haired woman who looked very, very cross.  _Wait, was that—Patricia?_

“Come now, Mr. Copper,” Regulus muttered.  “She’s not a monster.  She’s just a person.  What would be hilarious?” 

“Ridikulus!” he blurted, and the thing became a clumsy ballerina.  

* * *

“Tantellegra!” hissed Tulip, and Merula went down. 

“Miss Karasu, detention.  No dueling on school grounds.”

“She started it!” And yes, there appeared to be feathers everywhere on the young Ravenclaw. 

“Detention, Miss Snyde.  My office, tonight.  And 35 points from both your houses.”  It didn’t look like Slytherin was going to win this year. 

* * *

“She called Barnaby an idiot!” said Merula, waspish. 

“And she’s done the same to Ben a hundred times over.  At least with Barnaby it’s _true,_ ” Tulip replied. 

“Careful, or both of you are going to have more detentions,” he said.  “There’s a healthier way to do this, surely.”

“She uses Barnaby and Ismelda to intimidate people, then turns around and acts like they’re friends in front of teachers, and Barnaby doesn’t know an Animagus from a centaur, and—”

“Thirty points, Miss Karasu.  And more coming, if you don’t stop.”

He knew Barnaby tended to rely on partners in Potions, but he hadn’t been aware it had gotten that bad with other classes. 

“Miss Karasu, do you know what it’s like to not be good at something?” he began.  She shrugged. 

“I’m good at figuring things out eventually.”

“Everything?” he probed.  She paused. 

“I . . .”

“Because I know I’m not.  I’m not very physically strong; that’s why I was a Seeker and not a Beater in Quidditch.  I’m not good at making friends, Miss Karasu, and that’s cost me.  My family is good at holding grudges, and that’s cost all of us.  It’ll cost you, too.  And Miss Snyde?” Merula’s mouth twisted. 

“You and I know very well what it is you’re doing.  It’s what I did in school.  The war is _over,_ both of you.  I’ve lived it.  You have to work together to keep it from happening again.  Barnaby . . . he needs _help_.  More than I thought.  He doesn’t need people putting him down.  And Merula might actually be his friend, Tulip—just not the same kind of friend you’re used to.”

“I want you both to give me three feet of parchment on things you admire about each other and things you aren’t good at but want to change.  Once you are finished, give them to me and then head back—I’ll have Bill Weasley escort you, since he’s a prefect from neither one of your houses and therefore not as close to the situation.  Am I clear?”  The two nodded sullenly. 

* * *

“I want to institute a tutoring program,” he said at the next staff meeting.  McGonagall blinked. 

“Excuse me, Regulus?”

“Some students are falling behind through no fault of their own.  They may need some extra time or a different kind of teacher to work with them.  I would like to begin a system for that.”

“Excellent idea, Regulus,” Dumbledore said, eyes twinkling.  “Would you come to my office after the meeting?  I think we can come up with something together.” 

* * *

It was a quick thing, organizing tutoring—prefects and Heads of House would coordinate who needed help with who was best to give it, and students who were doing poorly would be given options to stay back and get help during different periods of the week. 

“Did you know that the Founders left behind specific artifacts in the castle?” Dumbledore asked.  Regulus frowned. 

“The sword of Gryffindor, the Ravenclaw Diadem—yes, I know.”

“And the Cup of Hufflepuff and Slytherin’s locket,” Dumbledore nodded.  “Regulus, these artifacts—they’ve been passed down through many different ways through the centuries.  I’m not sure about Hufflepuff or Ravenclaw, but the Sword has stayed with the Sorting Hat, that I know.  As for Slytherin . . . that stayed in the family, all the way down through the Gaunts.  Tell me, did you know what happened to the Gaunt family?”  Regulus shook his head.  They were all dead before his time. 

“Voldemort was Merope Gaunt’s only son,” Dumbledore said.  Regulus blinked. 

“ _What?_ ”  It was strange to think of the Dark Lord as anyone’s son. 

“And of course, that wasn’t his given name.  But, tell me, Regulus—did the Death Eaters know that Lord Voldemort was a half-blood?” 

“What?!”

“Ah, no then.  I guessed not.”  And then Dumbledore launched into a tale—that Merope Gaunt had fallen madly in love with a Muggle man, and how she lured him away, and how Dumbledore found Tom Marvolo Riddle at the orphanage.  Riddle.  His name was—

Regulus had to sit down, so he did. 

“Albus, why are you telling me this?”

“Voldemort was one of my students, Regulus.  You spoke of being close, helping students that needed it—it reminded me of all the students I failed to truly help.  Perhaps, had I not distanced myself, had I voiced my suspicions instead of believing a child couldn’t do the things he did—well.  That’s over now, isn’t it?”  Regulus grimaced.  That wasn’t the case. 

 _But Slytherin’s locket—_ locket!  That was—could that mean the Diadem, the cup—he wouldn’t settle for just three, though.  Seven seemed a likely number, one that would let him strengthen the bonds of magic over his shattered soul. 

He’d have to do more research. 

“We can only hope,” he mused. 

* * *

One of the last Hogsmeade weekends led him to go out with Dora.  She pulled him along and they met up with Narcissa, Andy, little Draco, Ted, and Lucius. 

“She keeping out of trouble, Reg?” asked Andy. 

“Hardly.  She and her friends are trouble,” he told her. 

“Atta girl,” grinned Ted. 

Draco babbled and reached for Dora, who was flashing her hair in different colors for his amusement. 

**Notes for the Chapter:**

> I am kind of breezing through HPHG because I want to have that time to settle Reg as a professor, but obviously I also want to get to Harry Potter years themselves. Prisoner of Azkaban is going to take up most of the time once we get there - a few chapters at least.   
> Sorry this one's short - comment your ideas for what you want to see, what you've liked so far, etc, and I'll see what happens next time! Pretty much I have 100 words of summary for the next chapter and the knowledge that Oliver Wood and Percy Weasley are going to both be there and they are both going to be roommates, so shenanigans will indeed ensue.


	4. A Preface to the Beginning

**Summary for the Chapter:**

> The Hogwarts Mystery students grow, and Regulus takes a step back from saving the world from the Dark Lord to do his day job.

“Three out of seven?” Regulus asked Bill dryly as he entered, Charlie and another redheaded boy in glasses following. 

“Percy,” Bill nodded.  “This is Professor Black.  Now line up with the first years to get Sorted, hm?”

“Hello, Professor,” said the little one, pushing his glasses up his nose.

* * *

“What do you _mean,_ first years can’t play Quidditch?” whined a voice. 

“Mr. Wood, you know full well we teach first years how to use brooms properly.  Only under very specific circumstances can the Head of House allow exceptions, and while I admire your determination, your safety is my priority.  Practice hard, and we’ll see about next year.” Regulus chuckled to himself, remembering his own insistence that he _had_ to play Seeker immediately. 

“You knew she wasn’t going to bend the rules for you,” Percy said a moment later. 

“But McGonagall loves Quidditch!  My dad said so!”

“She’s also a responsible professor, Mr. Wood,” Regulus sighed. 

He was going to get a migraine from Rakepick being here—the Ministry had sent her to unlock curses from former Death Eater students and teachers, and she was constantly breathing down his neck.  Curse breakers were tricky—they had to be tough and wily and willing to get blasted.  Rakepick preferred to just blast back, and her return to Hogwarts was no exception. 

First years badgering him about why they couldn’t join the Quidditch team yet, or why there wasn’t a dueling club like their parents had, certainly didn’t help his issues with her.  

She was there on “investigation,” whatever that meant.  Her searches through the Forbidden Forest upset Kettleburn’s creatures, so he had to make calming potions on the side. 

“Professor?” asked Bill as Regulus swiped his hair back from the cauldron.  “Are you . . . all right?” While he worked as a Gryffindor prefect, he was adamant that he be in contact with al of the Heads of House in rotation whenever possible. 

“Madame Rakepick has made my job a bit more difficult,” Regulus muttered.  “Wish more cursebreakers would take into account the effect they have on the places they visit.” Bill’s mouth twisted. 

“It’s one thing to break a curse; it’s another to disrupt everyone,” he agreed.  “I was just going to let you know Hera has recurring detentions in the kitchens for the rest of the month, so if you see her where she shouldn’t be, check her schedule.  Charlie issued the detentions and reported them to me.”

“Noted.  Thank you, Bill.”

* * *

And the thing was that Rakepick’s shady evasions weren’t even for curse breaking—someone had hired her as a bodyguard for a relic, and she’d failed by the end of term because she was dueling students outside her post. 

“You’re an adult,” he frowned.  “Why on earth would you fight students?”

“They’re stronger than they look,” she sneered.  “You know exactly how dangerous you were in school.  Why should now be any different?”

“We’re the authorities here, Patricia.  I don’t care that you’re older than me; I don’t care what I was like as a kid—I was stupid.  You didn’t you your job, and now these kids will think it’s okay to pick fights with kids when they’re older—you did it, after all, and got nothing but a slap on the wrist.”

“Getting off without punishment.  Familiar to you, huh?  When you’re still looking up dark magic?” she raised her eyebrows.  He grit his teeth. 

“You don’t know anything about what I’m doing.  Leave. Me. _Alone._ ”

* * *

 

Why the _hell_ would Albus hire her?

“It is Defense, and she’s a formidable dueler,” Dumbledore had reasoned when Grubbly-Plank had asked the same question.  “And it’s more punishment than anything—she’s being reassigned since she couldn’t defend the stolen artifact in it’s safehouse in Hogsmeade.  It will be brought here to the school when it is recovered.”

* * *

 

Ah, but Regulus was _right_ , dammit.  Take that, old man. 

That was probably not the appropriate train of thought as he dueled Rakepick with children chasing after Mugdungus Fucking Fletcher, who she’d been using to help her steal the Mirror of Erised, the artifact she’d been supposedly protecting. 

Stare at the mirror long enough, and you’d see your greatest desire.  Apparently, that was useful for some people, wanting to know what they could have that would make them happy.  That kind of thing could drive someone mad.  He was all too satisfied to see her taken down. 

Then, when Bill proudly told him he’d gotten a job as a Curse Breaker at Gringotts, Regulus grinned.

“I’m very glad to see someone with tact and actual talent will be taking that woman’s place.”

Bill’s grin was wide—it reminded Regulus of the little first year that had insisted he’d tell everyone what an amazing professor Regulus was.  He said so, and Bill laughed. 

“It was the truth, Professor.  That’s the point, isn’t it?”

* * *

 

Without Rakepick there to irritate him, he found that he could dive back into figuring out Voldemort and horcruxes in between classes the next year. 

_If it weren’t for those bloody Weasley twins_.  Fred and George were menaces, and Charlie could have been a bit more willing to clean up after their messes as a prefect.  Instead, it seemed Percy gave himself that role.  Their very first night, they’d figured out how to floo call the other House’s fireplaces, pretending to be cursed spirits. 

Of course, also in the wake of Rakepick, Hera seemed to have a new need to find her brother, who’d gone missing before Regulus had begun teaching.  He tried to remember whether he’d known Jacob or not—it was hard to remember the first years when he’d been so focused on the older students, on pleasing them and joining up with the ranks of Death Eaters.  Regardless, he did what he could to help her—while avoiding Peeves, of course, who wanted in on the project in exchange for help with pranks.  Duncan Ashe had become his ghostly accomplice. 

Though the Weasley twins recruited their friend Lee to do it all behind everyone’s backs, getting help from Hera and her friends whenever they could weasel it out of them, Regulus still caught the twins on occasion and had to send them to Filch’s office for detention.  They didn’t seem too unhappy about the situation. 

And they didn’t get caught for the rest of the year, despite the continued, if less dramatic chaos.  It was almost like they knew where everyone was, much like Sirius and Potter had when they were kids. 

While that was happening, Regulus had to tutor pretty much everyone in Defense, because Mundron, the current professor, wasn’t any good.  During a meeting with staff, he complained about it to Flitwick, who shrugged.

“Everyone’s pretty sure someone jinxed the job, after all.  You’ve noticed there’s a new one every year, right?  It didn’t always used to be that way.  After old Caleb Theylas retired, it’s never been the same.  Perhaps an applicant that didn’t get it was upset by Dumbledore’s decision.  Or maybe one of Theylas’s old enemies missed him on the way out.  After all, it’s been decades, and we haven’t held a Defense professor for more than a year.  Too much to be a coincidence, no?”

But how would that jinx work?  It would take considerable power and time to even specifiy it to a job, a title, rather than a place.  Hogwarts was hard enough to place ritual curses in, so it was impressive that someone had managed it.  Despite being the tutor, Regulus made it clear: he did not want Defense unless the jinx was removed or he was going to retire the next year. 

* * *

 

The lucky thing was that Penny Haywood had begun mentoring a second-year to be the next best student in his class: Cedric Diggory, who more than made up for Fred and George’s antics.

Regardless, the years following Rakepick’s downfall were whirlwinds trying to find time to do much beyond his actual teaching duties and spending time with his cousins’ families.  Summers gave him some time to find dead ends on his Horcrux and Voldemort-history research.  None of it was useful.  Perhaps he might not need it though. 

Perhaps whatever had supposedly destroyed Voldemort had disconnected him from the artifacts.  With seven shattered pieces, how could there be enough of him to pull himself to return to the land of the living?  How would he even get a body of his own?  There were too many factors, and no signs of the Dark Lord acting, so it hadn’t been a terrible worry to step back from his research for a little time. 

Hera and her friends—which, by the end, had included Merula—had all found jobs waiting for them, and they were all very confident that they knew what they would do.  Charlie assured him that Bill had gotten a job at Gringotts, and that he was going out to Romania to a dragon sanctuary.  Barnaby was joining him.  Penny and Rowan were taking over shops in Diagon, and everyone seemed to find the right places for them.  Regulus was pleased. 

Until he received his Daily Prophet that August. 

_An attempted robbery at Gringotts?_

**Notes for the Chapter:**

> Sorry for the short/rushed chapter; I don't have any of the rest written quite yet, but I did want to set things up for Harry and co to come to school. Sorcerer's Stone should take up a chapter or two, Chamber of Secrets should be about the same, and Prisoner of Azkaban will be the longest, of course.


	5. The Potions Master and the Boy Who Lived

**Summary for the Chapter:**

> From the break in at Gringotts to Halloween, Regulus has found that Voldemort is going to make his move.

_How in hell did someone break into Gringotts?_ Regulus stared at the article.  Those spells were beyond him. 

What was worse was the next immediate problem: who would be powerful enough, who would want to be immortal that badly?

Who else?

Almost immediately after the thought clicked, an owl flew into his study, flapping urgently.  He took the letter. 

_Dear Professors,_

_It has come to my attention that the Sorcerer’s Stone, which was the item stolen from Gringotts, is going to be kept here at the school, as we have the next best security in the interim.  I am asking all professors willing and able to contribute to levels of trials to keep students and other perpetrators from getting to the stone.  Between all of us, this will make things far safer. Please reply with your decision within two days. Those who agree to this will have to come to the school a week earlier than usual._

_Regardless, students will be forbidden from going into the area, and more safety measures will be discussed._

_This year, as well, Harry Potter will be coming to school.  Please treat him as another of your students, not as a celebrity._

_Best,_

_Albus Dumbledore_

While Dora complained to him about Auror training, Narcissa asked him if he’d tag along to take Draco shopping.  Regulus sent off a quick owl to Dumbledore.  He’d given Regulus some valuable hints.  He might as well help with school security.  He might be able to get more out of the old man if he talked with him about it, though. 

And Harry Potter—he thought about Lily Evans, who’d tutored younger students, who’d suffered by Snape and their friends for longer than most had patience for.  And James Potter, who’d taken his brother from him and his family, only to get killed for it. 

This boy wouldn’t have known either of them.  Regulus wouldn’t have a problem with it at all, would he. 

Right.

Meanwhile, he put on some nicer robes and went out drinking.  Might as well have some fun before figuring out the wards he was going to put down. 

* * *

“Mother,” Draco sniffed.  “Are you quite sure I’ll even need a new cauldron?  We have one at home that—”

“You’re a new student, same as all the rest,” Regulus interrupted.  Lucius shot a piercing glare to Regulus. 

“But I already know what’s coming,” the little boy protested.  “Why should I have to wait like I don’t?” 

“You will get what you need,” Narcissa assured him.  Lucius said a quick goodbye and broke off to go to the Ministry for business.  They went to Madam Malkins, and Regulus waited outside while Narcissa went to Flourish and Blott’s to get books. 

After a short while, Hagrid began approaching the shop from Fortescues, holding two large ice creams. 

“Ah, Regulus!  Good to see you.  Waitin’ on someone in there?  I’m escorting young Harry around Diagon, y’see,” he gestured into the shop, waving from the window with a big grin. 

“Shouldn’t his family . . . ?” Regulus asked, but Hagrid shook his head. 

“They don’t care for magic none.  I had to deliver his letter myself after they kept him from readin’ his.  He didn’t even know about our world ‘t all.  Hey, there!” he grinned as a young boy came out of the shop, robes in a bag.  The boy was small, made even more so by the baggy clothes he wore.  He stared up from his mop of black hair with bright green eyes.  He clearly had been brushing it down with his hand to cover his scar, awkwardly plastering it over his forehead. 

“This is Regulus Black.  He’s going to be your Potions professor at Hogwarts,” Hagrid smiled. 

“It’s good to meet you, Harry,” Regulus said, nodding.  “I suppose you’ll be getting a treat before continuing your shopping trip,” he gestured to Hagrid before holding a hand out to shake.  Harry took his hand and shook it firmly, still looking up at him warily. 

“I’ll be seeing you at school, Mister Potter,” he gave a nod.  The boy nodded and trotted off with Hagrid.  A few minutes later, Draco came out, looking up at him. 

“Make a friend?” Regulus asked. 

“Hmph.  He didn’t say much.  Didn’t seem to know anything.  Probably Muggleborn,” he sniffed, and Regulus sighed. 

“You use that as a way to measure your friends, you’re going to have a hard time of it, Draco.  That was Harry Potter.”  Draco’s eyes widened, but by then, Narcissa had caught up with them, and they were off to get him a pet.  Regulus really hoped he got a sensible owl, and not a cat or toad. 

* * *

 

He consulted his library for ideas, but it did end up running right into the week he was meant to go back to school as he planned his protection for the Stone. Everyone had good input, even Quirrell—he couldn’t blame the professor for being twitchy.  The man was clearly aware that his position was temporary, looking about for the danger that would take him out of it. 

McGonagall’s chess was violent, but effective, and one person alone couldn’t enter that way, so there was less of a chance of stealth—if only one person could even sneak into the school.  Regulus didn’t doubt it was possible, though.  After all, if someone could break into Gringotts—well, they’d be formidable enough.  Years before he might have been surprised by Dumbledore’s trust in him to create any sort of defense, but apparently it was worth it. 

It technically _was_ potions-based.  But Voldemort was arrogant about magic and his power, so he may well fall susceptible to something outside magic—or at least be slowed down by it.  A series of logic puzzles—not just one, of course, but enough to slow anyone down at least long enough to make sense of things.

Nothing deadly, but a few potions to knock people out for a long time until someone could come collect them. 

* * *

 

The start of term was the same as any other, except for half-bloods and purebloods alike murmuring about _Harry Potter, he’s in first year, you know?_

The nervous first-years lined up for Sorting.  Regulus listened for familiar names—children of people he knew were starting to come up, though they were mostly children of fellow classmates in upper years. 

Crabbe—quite like his father, quickly sorted with as gruff a nod as an eleven-year-old could muster.  Goyle, much the same, followed by a muggleborn girl with frizzy hair that went to Gryffindor.  Longbottom—Regulus winced.  No doubt that would be difficult, thinking on Bella.  He knew the Black family had some similar features.  He’d keep an eye out. 

Draco was smug as he went to Slytherin, joining the two larger boys he’d been standing near by the door.  Then Harry came up, and the hall quieted.  Regulus sighed to himself.  Either this boy was going to have a terrible ego, or he was going to need bailing out of a lot of celebrity-induced chaos. 

Another Weasley boy—Ron, if he remembered Fred and George giggling about some spider prank—nervous as could be, went up to the Hat.  Perhaps _this_ one wouldn’t be Gryffindor?

Nope.  The boy slumped, relieved, and joined Harry just near Percy and the twins.  The last one was Blaise Zabini, Cecilia’s only son—Regulus would have loved to pick the kid’s brain, had he been in his class, wondering if the woman had really killed her husbands.

After Dumbledore’s address and dinner, Regulus motioned for his upper year students to head to their rooms before the prefects led the first years.  He hurried to the common room to beat them there by a few moments. 

“Hello, first years.  I’m Professor Regulus Black, and I’ll be your Head of House for the foreseeable future.”  The students stared up at him, rapt.  He smiled a little—the young ones were very easily impressed. 

* * *

“Here you can put away your wands.  This class is all about balance, timing, reactions, and patience.  You follow directions, you make a good potion.  You pay attention, you figure out what works and what doesn’t.  When you’re more advanced, you can figure out ways to twist the original directions, make things more or less effective, make things last, add side effects—but until you have a deep understanding of things, you must follow directions to know _why_ things work.”  He glanced at the students, who were looking up at him.  Right.  Class.  With Gryffindors and Slytherins.  He started asking questions. 

Hermione kept raising her hand—while he appreciated the enthusiasm, he sighed. 

“Miss Granger, if you are the only one to ever answer questions, no one else is going to learn anything new,” he said.  “Thank you for reading the book ahead of time, though.  Ten to Gryffindor.  Now, can everyone who has also read the book please raise their hand and tell me one thing they remember from the text . . . Miss Parksinson?”

“Pompion briefly turns the drinker’s head into a pumpkin,” she said.  Regulus nodded. 

“Five to Slytherin.  Ah—no one else?  Hm?  Mister Potter, are you stretching or raising your hand?”  Harry slumped. 

“Ah—Dittany?  Is an herb for healing, I think?”

“Correct, Mister Potter. Five to Gryffindor.  Now, today I want you to copy down the directions for the Cure for Boils potion . . .”

* * *

 

Draco came to him in a huff about Potter and Weasley not two days later.  Regulus rolled his eyes.  He’d tried to goad them into a midnight duel, and admitted it outright. 

“Detention, and fifteen points from Slytherin,” he immediately issued.  He looked shocked at the idea.

“But—Professor— _Uncle Regulus_ —”

“You’re a student, same as others, Draco.  Dora got detentions from me, same as from her Head of House, same as other professors.  I can’t play favorites, and what you did was something dangerous.  What if they’d actually gone out and taken you up on it?  They could have been injured, had they tried to run and take a wrong step into the wrong corridor.  They would have gotten detention if they were caught out, too.”  He sighed. 

“I’m really going to have to restart that Dueling Club.  It’ll certainly get this aggression out faster with proper supervision.  One way or another, Draco, you’re going to have to organize the first-year Potions ingredients tomorrow night after class until dinner.”  Draco’s cheeks were pink, but he didn’t look like he was more than frustrated, so he sent the boy back to his rooms.  He had plenty of time to kill before the first essays started coming in. 

It was time to talk to Dumbledore. 

* * *

 

“Albus?” he asked, the name still weird on his tongue.  Only certain teachers were the types that he could easily call by first name—Dumbledore was not one. 

“Regulus!  Come, sit,” he gestured.  “Lemon sherbet?  Tea?”

“Tea, please,” he nodded.  “I admit I’m surprised there hasn’t been an attempt on the Stone.  Believe me, I know you probably kept it secure and secret, but we both know Hagrid is not good at keeping his mouth shut.”  The headmaster’s eyes twinkled. 

“You think so?  Hm.  I do trust him, but perhaps secrecy is not his strong suit.  Why did you want to meet tonight, then?”

“I believe the Dark Lord is not dead, and that he is going to try his damndest to get the Stone, sir,” Regulus said.  Dumbledore raised his eyebrows. 

“And how did you come to this?  I don’t disagree, Regulus.”

“He created horcruxes to stay alive.  At first, I thought it was just one, but . . . he’s split his soul more than once, I’m sure of it.” 

“How do you know about this?”

“He’s arrogant, Dumbledore.  He bragged, never saying the exact terms, but I found a little information after one night and he’d asked me to lend him my house elf for the endeavor.  He’d hidden a locket—Slytherin’s locket—in an old cave on an ocean cliffside.  Guarded by Inferi.  He spared no expense.”

“And he underestimated your house elf’s ability to survive it,” Dumbledore nodded.  “I see.  What became of the locket?”

“I have it secured in one of my estates,” he said.  “Do you know anything I can use to destroy it?”

Dumbledore nodded.

“Potentially.  Spells, items that completely consume or kill—really, something instantly deadly to a person with strong magical protection.  That’s what a horcrux is, Regulus—a piece of a person with its own magical warding.  Do you think Voldemort would have had a particular number?”

“Seven, likely—or six, including himself.  He was quite fond of using magically strong numbers to get better results.  Only so many members on a mission, and all.”  Dumbledore sighed. 

“Right.  We may have to find out _how_ they are made to track them down—a timeline of who got what and why.  Does that make sense?”  Regulus frowned. 

“I don’t want anyone else making horcruxes, Dumbledore.  I want the existing ones destroyed.  This kind of magic shouldn’t exist.”  The headmaster hummed in reply. 

“It certainly shouldn’t.  And Voldemort, I have cause to believe, is going to try and collect them—through a loyal follower, perhaps, since he can now only live as a husk of his former self.”  Regulus remembered the red eyes, the snake-like face, the voice scraping across his eardrums. 

“He was a husk of a person to begin with,” he muttered.  Dumbledore agreed.

“I know you don’t trust me entirely,” he said.  “And I have few allies that I’ve made aware of this.  But Voldemort, as I’m sure you remember, has a way of convincing people to do things for his cause.”  Regulus grimaced. 

“I would ask you to personally guard the Stone, Regulus, if suspicious activity happens.  Until we can be sure of anything, I can’t have anyone I don’t trust to do the right thing there.”  Regulus stiffened. 

“You trust me, Dumbledore?”  The old man laughed.  

“I know you don’t trust me, but you care for your students, and you want Voldemort ended.  Those combined prove more than you think,” he said. 

The little boy in Regulus that still wanted to call him ‘headmaster’ and worry about points being taken away preened at the praise.  He gave the man a wry smile. 

“Make sure to hold your allies to the same measure, Albus.  Voldemort has no sentimentality for his followers; it’s only power and loyalty to him.”  Dumbledore made an agreeing noise into his tea as he sipped it. 

“Voldemort also has a certain flair for choosing dramatic moments.  If his fall was on Halloween, I would guess that he would try for the stone on the same day.  Be on alert, Regulus, and should anyone try things, I leave it in your hands to look out.”

Right.  No pressure, headmaster. 

* * *

 

“TROLL!  Troll in the dungeons! . . . thought you ought to know,” and then Quirrell collapsed onto the floor.  Regulus stood up immediately as students began screaming, turning to his prefects even as Dumbledore ordered them to their rooms. 

“Slytherin, to the library, like we discussed.  Prefects, follow Madam Pince’s directions, and do _not_ leave.”  He hurried upstairs to the third-floor corridor to see Quirrell in the hall. 

“I thought you might get rushed to the Hospital Wing, Quirrell,” he said through clenched teeth.  “You were a Ravenclaw.  Imagine the answer to this riddle: a troll gets loose that you were in charge of.  And then you go to the chamber that it escaped while no one’s around to watch.  How many curses do you think I’d cast if I thought you were doing something you shouldn’t?”

“I’m n-not the one with the D-Dark Mark, Black,” he stammered.  “Who was You-K-Know-Who’s servant in the war?  You, uh, aren’t exactly the m-most trustworthy p-person.”  His eyes were wide and his hand was shaking.  Regulus crowded him towards a wall, growling. 

“I don’t appreciate the insinuation, Quirrell.  If you make the wrong move, someone might mistake your injuries as something you got when you fell in the Hall.  You’re messing with something you don’t fully understand.”

“P-perhaps.  But you don’t know everything, B-Black.”  Regulus scoffed and shoved him away from the door, glaring him down until he retreated.  Then he headed towards the dungeons. 

A commotion came from down the way, and he rushed over only to find the mountain troll unconscious on the ground, three first years standing around, and the other professors in the process of hustling them out. 

“Did they actually . . .” asked Regulus.  McGonagall was white as a sheet. 

“They did,” she nodded. 

Harry Potter, Ronald Weasley, and Hermione Granger stared up at him, grimy and tired and _far too small to fight a troll_.  He held back an exasperated sigh for the sake of professionalism, but he tried to give them a glare that conveyed it while smiling and nodding appreciatively. 

He probably just looked creepy, but whatever the case, no one had been seriously injured, and he was sure Minerva gave them the appropriate reward.  He went to the library to check his students—scared, but otherwise not making too much of a fuss in the library, and only one sixth year had tried to sneak into the Restricted Section in the meantime. 

He counted that as a success. 

**Notes for the Chapter:**

> I wrote this in the expanse of a few hours, so it's certainly going to be as fun as I think to do Prisoner of Azkaban. I had way too much fun with this, okay? I don't want to totally break timelines, because I still want the kiddos to have their lives, but I think Regulus being an actually decent prof will be fine. Harry's still going to suspect him, Neville is still going to be scared of him (because of Bella looking like him etc), and despite his best efforts, Draco still turned into a little shit. 
> 
> Comments and kudos give me life! See y'all later!


	6. Death Eaters and Dark Lords

**Summary for the Chapter:**

> The second half of the year comes - Regulus visits family for Christmas, and he disapproves of Dumbledore's child safety practices.

Regulus didn’t even want to know what McGonagall did to get Potter on the Quidditch team.  It was a sight to behold, for sure, watching the boy zip around the field.  He frowned when the broom started jerking around—a jinx of some kind?  He began muttering a counter, keeping his eyes on Harry.  It was either that or look for the culprit, but in the meantime the boy could be thrown from his broom. 

Keeping students safe was the priority; catching the culprit was next.  He was a few minutes in as Harry steadied himself. 

The smell of smoke and the heat at his ankles broke his gaze and he twisted to put it out—but Harry had righted himself, so the disturbance had affected the one jinxing him, too.  He glanced about, but Harry had zipped off, and everyone had stood up, so he turned back around—Harry was hunched, heaving like a cat with a hairball. 

And he held up the Snitch, moments later.  Now _that_ was a way to start a Quidditch career.  He almost felt jealous, thinking of his times practicing, chasing charmed paperweights around the foyer.

* * *

“Professor Black?” asked Neville, “What size should I chop these down to?”

The students behind him snickered. 

“Good question,” Regulus said evenly, “And one that works as a lesson on ingredient care.  If you have too large pieces, what happens?”  Harry raised his hand. 

“They take longer to boil down with everything else?”

“Was that a question or an answer, Mr. Potter?” Regulus raised an eyebrow.  The boy flushed and told him that it was an answer.  Regulus continued to explain that yes, that was the case, but steeping the potion too long would render the other ingredients less potent, and would shift the effects towards less pain-killing, but more bringing down inflammation.  A balance was key. Regulus demonstrated the correct size for the sage—about the length of the average first-year’s pinky finger was enough. 

“But do _not_ line your fingers up to be chopped,” he said. 

The holidays came quickly, and the Weasley twins found it important that they batter Quirrell with snowballs in the back of his turban, followed by red and green glitter plastered to Regulus’s clothes and subsequently everything he owned. 

The second part wasn’t a charm; that was just the glitter. However, he didn’t stay

Regulus had a standing date, one that he’d promised himself he’d do ever since he’d seen Harry Potter come into his classroom. 

He was going to visit Sirius for Christmas. 

* * *

Azkaban was filled with moans and screams, spilling over with them at the outskirts, followed by deathly stillness as he approached the prisoners that had been there the longest.  Few people got access to visit Azkaban, and he’d originally worried that he wouldn’t have access, but apparently the lack of visitors was more of an enforced choice—only people with very specific reasons to come to Azkaban would, and they would get a background check, but if they passed, they could keep personal items on them, even their wands.  Regulus passed by cell after cell before hearing a babydoll-high laugh. 

_Merlin’s balls_ if he’d never wanted to hear that again. 

“Who’s coming to visit?  You know it’s not safe for someone to lurk about,” she said, approaching her cell door.  Pale as hell, like all the inmates, emaciated.  He wondered whether she’d broken before or after the dementors, whether she was immune or putting on a front.  He didn’t answer, but he didn’t continue forward either. 

“Ooh, did someone come to see me?”

“No, but I doubt anyone will mind if I make a second stop,” Regulus said.  He spun on his heel to face her.  Her eyes were wide and blinking as she took him in. 

“It couldn’t be— _ickle Reggie?”_ she began to cackle.  “What could you possibly have in mind for me, hm?  Come to see your big brother?”

“As a matter of fact, yes.  It is Christmas, after all,” Regulus said, tightening the fastenings on his cloak.  The dementors made it freezing in the place. 

“And why _this_ Christmas, of all times?  Don’t tell me you’ve come to free him from this place,” she sneered.  “Filth shouldn’t even be here, pathetic that he is.  How’d you get out of it, anyway?  He was raving and sobbing and the lot from the beginning, but the past few years he’s quieted down.  Think he might not be there anymore, Reggie.” She was pressed up against the bars, a tiny twitch ticking in her right cheek.  Hell, most of her was trembling—for what, he didn’t know. 

Regulus started walking.  He didn’t need to explain himself to her.  What did he owe her, anyway?

_Sneaking sweets under the table.  Backyard Quidditch.  Practicing French._

He reached into his robes for a box of madeleines, sighing.  Perhaps he’d face Sirius another year, then—Bella could be lying, but she could also be lacing it with the truth.  As far as he knew, the dementors hadn’t given Sirius the Kiss, but these central cells . . . it was hard to tell who had and hadn’t.  Maybe there wasn’t anything left of Sirius to give it to, anyway.  _Yeah,_ he told himself, _good excuse. Sure._

“ . . . Merry Christmas, Bella.”  He handed her the box through the bars.  She looked curiously at them, opening the box and taking a bite. 

“Merry Christmas, Regulus,” she said.  It sounded like an echo, almost hesitant and strained.  He nodded and turned away. 

He’d had enough of Azkaban and the cold burn of Inferi screaming in the back of his mind. 

* * *

He’d watched Quirrell on patrols as a cat, but even his Animagus form couldn’t bring him more time.  He had students from all levels to take care of, his own duties, his own studies on Horcruxes, now that Dumbledore was willing to work with him on finding more information. 

So when apparently, Harry Potter caught Voldemort drinking unicorn blood, it hadn’t caught his radar, because he’d been grading papers that night.  And when Dumbledore got called to the Ministry, he hadn’t thought a thing of it—not until the alarm for his protection for the Stone went off, once, then again just a few minutes behind.  He got up from his desk and stormed downwards, a cluster of teachers doing the same alongside him.  They swept through one thing after another—a sleeping three-headed dog from Hagrid after someone charmed the harp already standing there to play. Through the others’ defenses. 

Then they stood in Minerva’s chess set, Hermione Granger cradling an unconscious Ron Weasley, and she yelled that Harry had gone to face Voldemort and that they had to hurry. 

What they found was a dreadful sight—Harry, passed out in the mirror room, the Stone inches from his outstretched palm and Quirrell dead at his feet, burned and disfigured.  Minerva rushed towards Harry, hauling him up in her arms, wand ready as if the dead Defense professor would reanimate at any moment. Regulus nodded for her to leave and inspected the body—it was as if two faces existed on one head, one horribly snakelike and familiar for all it seemed to grow out of the wrong part of a skull.  He pulled up Quirrell’s left sleeve—the burn marks and crumbling, ashy body didn’t make identifying a Dark Mark easy, but it was there, forearm darker than the right in just the same position as Regulus’s. 

While the others dismantled their enchantments, Regulus scooped up the Stone, grimaced, and stormed towards Dumbledore’s office. 

“Get the students to the Hospital wing,” he told the others. “I’ll inform the Headmaster.”  Ah, inform, what a beautiful term for the swearing and berating he was going to get no reaction from and then get a gentle explanation that would leave _him_ feeling like the bad guy.

* * *

“— _Eleven years old_ , Albus, and you knew perfectly well that keeping things secret at Hogwarts never works, and it was practically tailored for them to get in. And if a trio of eleven-year-olds could do it, how would you expect Voldemort to be deterred?  He could have died!” he raved.  Albus raised an eyebrow. 

“Harry was perfectly safe from the clutches of death, Regulus.  Voldemort cannot kill him.  Lily made sure of it moments before Harry received that scar of his.  Her sacrifice rendered it impossible for Voldemort to do Harry harm.” 

“And if it had been Quirrell alone?” Regulus asked.  “If Voldemort hadn’t possessed him, had let him go on ahead?”

“After you nearly caught him on Halloween?  Voldemort’s hardly the type to let failures go, Regulus,” Dumbledore said.  Regulus, exasperated, sighed through his teeth. 

“This doesn’t change the fact that you left, knowing You-Know-Who was in the school, for a letter from the Ministry you would usually ignore for a few days.  And you put that boy through unnecessary grief in the process.  Do you realize that?  Just because he _could_ survive it didn’t mean he _had_ to.”  Dumbledore’s eyes darkened slightly. 

“And would you have faced him?”

“I would have killed him on the spot, Albus,” Regulus snapped. 

“No, _he_ would have killed _you_.  He doesn’t see Harry as a threat in of himself as a duelist.  I knew he would survive it with certainty, Regulus, but I didn’t have that guarantee for anyone else.  I couldn’t afford to lose someone for this.” 

“ _You_ would have survived it, and Voldemort would not have dared if you hadn’t kicked out Quirrell the minute you suspected the possession.”  Dumbledore shook his head. 

“And don’t you think Harry needed to face him?  The one man who took everything away?”

“I think he’s too young to think about killing a man, Dumbledore, and if you so much as _mention_ that he killed Quirrell to him—not intentionally, of course, but still—and you didn’t even _tell_ me that Quirrell might be a threat!” Regulus was too angry to focus on one thing or another, but Dumbledore had answers.  He always did, whether he should have or not. 

“Quirrell was dead the moment he allowed Voldemort to attach to him like the parasite he was.  I didn’t know any more than you did about Quirrell from the start, but the unicorn blood?  That meant that Voldemort was barely hanging on, feeding off of his life force.  No doubt he would have eventually eaten away at Quirrell and withered the body away to little more than a husk.”  Regulus cursed, but he didn’t have anything particularly coherent to say beyond that for a solid minute.  He huffed, then looked the headmaster in the eye. 

“What do you intend to give those children in compensation for fighting your fight, then?” Regulus asked.  “I knew you weren’t against recruiting young, no more than the Dark Lord—future Order members and Death Eaters alike were ready right from the classroom after all—what could you possibly do for them?”

* * *

Apparently, Dumbledore was more than capable of being petty, because by _ten fucking points_ , Gryffindor got the House Cup, just like that, just at the end.  He’d really asked for it, hadn’t he?  He glared at Dumbledore through the rest of the closing feast, cursing himself as he dug into his food.  So he probably looked like a petulant child—it didn’t matter.  He’d done it to punish him, complying with his request to reward the young Gryffindors involved, but he was only suffering because his students were unhappy.  Dumbledore really was a crafty old bastard, after all.  It was enough to make Regulus refuse to stay at Hogwarts over the summer, insist he could do research on his own, and send a howler detailing over again all the things he disapproved of Dumbledore's choices that year. 

For the summer, Dora was on her first long-term Auror mission in Spain, so Regulus elected to stay with the Malfoys that summer rather than be entirely alone with Kreacher.  Lucius didn’t like him, and Draco was sulking _still_ about the detention he’d given him, so he spent most of his time in the library and gardens with Narcissa.  At least then he could get some peaceful, non-passive-aggressive conversation. 

**Notes for the Chapter:**

> Okay, I know ahead of time that Chamber of Secrets is probs going to take a while, because only really the ending has any interest to me and the rest will feel like a filler episode. The positive of that is that I'm probably only going to take one chapter to do it, so we will finally get to the whole point of this fic sooner than later.   
> Bet y'all weren't expecting Bellatrix! I wasn't either until I started in on it - I wanted to get Regulus there, but I didn't want him to actually talk to Sirius just yet.   
> Hope this chapter was worth the wait - I really needed to just do it rather than wait. I have so many weird feelings about how Azkaban was potentially run, so if you'd like a more in-depth discussion of how I think it worked, I am more than willing to rant about it in comments or in my next author's notes.


	7. Venomous Steps

**Summary for the Chapter:**

> Regulus feels like he's constantly playing catch-up on this horcrux hunt, and students being petrified doesn't help matters.

The summer ended up being mostly uneventful.  Of course, there was the upset of Lucius apparently fighting Arthur Weasley in public—Regulus would have paid good money to see a proper Malfoy man get decked, but sadly, he’d had to skip that particular trip.  Instead, he’d finally floo called Albus, ranted a bit about how he had _not_ meant punishing his students for the sake of Potter and company’s glory, then asked about Riddle’s personal life to see if he could get locations on the other horcruxes. 

“Oh, we have contact with two of Tom’s fellow classmates,” Dumbledore said, “Although, one didn’t know him well, and the other doesn’t much want to talk about their school days together.  I doubt you’ll have much luck with it, Regulus.”  He frowned. 

“Any information is better than none, Dumbledore, and you were his professor—surely you—”

“Ah, but how many things do you talk about with your classmates that you wouldn’t dare say to your professors?”  And of course, that might be true.  But it was _Dumbledore._   He tended to find ways to know everything. 

“I’m not all-knowing, Regulus.  I try my best, but I’ve found out with every passing year just how little I really know.” 

“And anything is better than nothing, so who are they?”

“Myrtle Warren and Rubeus Hagrid,” said Dumbledore, and Regulus cursed again.  Maybe this was the step it took to be able to feel like a peer around his old headmaster—though he doubted he’d ever be quite as comfortable as Minerva was around him. 

The trip he unfortunately could _not_ skip was the early one to Hogwarts, after which they got to know the new Defense professor.  The Ravenclaw Regulus had hoped never to meet in person again. 

“Well _I’m_ sure Regulus’s proposal will require more than just one professor present!  I’d be happy to be an expert on hand to draw student interest,” said Lockhart.  Regulus deadpan glared at him, but apparently, no one was willing to bail him out of this one. 

“Having an assistant would be great, yes,” he ground out.  “It takes at least two to duel, after all.”  Lockhart only smiled again, nodding along. 

* * *

Regulus had elected to leave the welcome feast early as he had the past few years, and once he’d settled his students in, had planned on getting to bed early.  But apparently, Harry Potter and Ron Weasley had other plans. 

“What do you _mean_ they flew a car into the Whomping Willow?” he grumbled, desperately wishing for bed or brandy.  Whichever came first. 

* * *

He wasn’t pleased to find that Lucius Malfoy had undone whatever progress he’d made with Draco.  Despite spending a whole summer with them, he’d kept to himself and Narcissa too often. 

Hermione had come to him, hesitant. 

“Professor Black,” she said quietly.  “I hate to bother you, sir, but . . . Draco called me a Mudblood.”  Regulus had to bite his tongue to not swear out loud.  _Bloody Merlin’s fucking bullocks_.  Instead, he rubbed at his temples and leaned forward on his desk. 

“Thank you, Miss Granger.  Can I ask why you didn’t go to a prefect for this?  I can’t imagine he did it right outside my office.”  She looked down with color rising in her cheeks. 

“Well, Ron tried to hex him, but his wand’s been broken, so it backfired . . . and any prefect might dismiss it.  I don’t know who agrees with his ideas and who doesn’t.”  She tilted her chin upwards at him, and he knew she was a Gryffindor for a reason. 

“Ah, that can be an issue.  But I assure you, Miss Granger, I would not conventionally be the professor I would think you would go to for this.  How did you know _I_ wouldn’t stand for it?”  Her eyes went wider. 

“You’re a professor!” She sounded outright scandalized, and he chuckled. 

“So was Quirrell, Miss Granger.  I am the Slytherin Head of House, a pureblood from an old family, and Draco’s cousin once removed.  You’re right in thinking I’m going to punish him for this, but next time?  Go to one of the Gryffindor prefects, please.  I appreciate your trust, but there’s a system for a reason.”  She flushed again and nodded. 

“Thank you, Professor.”  Regulus sighed and was sure to call Draco aside during his free period.  He took the boy to his office and sat him down, glaring. 

“I’m disappointed, Draco,” he said evenly.  The boy looked down at his lap.  Regulus sighed. 

“Do you understand why?” he asked, and Draco said nothing, glaring petulantly at his hands folded on his knees. 

“Draco, I’m asking you a question.”

“I’m _thinking_ ,” he said.  Regulus began contemplating what the punishment would be—points taken and some sort of productive detention, yes, of course.  But how severe should he be?  He did care about Draco, for all he was frustrated with him. 

For all he was afraid of him making the same mistakes.

“I called Granger a Mudblood and she told you,” he said.  “What part of that are you disappointed in?” Regulus remembered being twelve, thinking he knew everything he needed to. 

“I’m frustrated for a lot of reasons. Partially because I’d hoped I’d never hear that term again plenty of years ago, and I wasn’t so lucky.  Because that word and what it stands for was part of the reason your godfather lost his last chance with his best friend.  Because I used to refer to people with that word, and I thought the exact same things you think about them—that I was better, that I was noble, that I had a better standing.”

“You _are,_ ” Draco insisted.  “The Black family—”

“Is no older or younger than the Granger or the Finch-Fletchley or the Longbottom family—we just kept track of things, controlled who we married.  Her blood, and the blood of other muggleborns, isn’t dirty, Draco.  It bleeds exactly as red as yours or mine.”  Regulus paused.  He hadn’t been asked in years about being a Death Eater.  He was sure Draco knew about Lucius’s Mark, but his?  He’d kept that to himself.

He pulled up his left sleeve. 

“Draco, I have seen what that kind of thinking does to people.  And I won’t see that happen again, not if I can help it.” His eyes widened, and he looked up at Regulus with confusion. 

“You served the Dark Lord?”

“And I regret it,” he said.  “I don’t want to see you getting killed the way I nearly did.  So—if it ever comes to joining up any sort of group that even seems like the Death Eaters—tell me.  I can’t . . . I can’t see that happen to you.  You’re family, Draco, and I won’t see you make my mistakes, all right?  You’re smart.  I’m hoping you’re smarter than I was.  So I’m not going to give you an average detention—I’m going to put your brain to work.  Can you _please_ tutor Crabbe and Goyle, since you enjoy their company so much?  They desperately need the help.  Also, twenty points from Slytherin.  Don’t use that language, Draco, but more importantly—keep in mind _why_ you shouldn’t use it.” 

His cousin looked back into his lap for a few moments before meeting his eyes again. 

“Yes, Professor.”

* * *

_The Chamber of Secrets has been opened.  Enemies of the Heir beware._

Well, unless Voldemort had found a new host in fucking Gilderoy Lockhart, he very much doubted the Dark Lord was actually responsible for this one.  His mind flitted through his own students, wondering who could be the potential culprit, but none of them seemed to stand out as particularly willing to Petrify anyone with this kind of spectacle.  He began researching petrification curses, wondering how it could have happened.  By the time the Dueling Club first meeting had been set up, he hadn’t done much else but grade papers and wonder why the hell none of the countercurses were working. 

Professor Sprout, luckily, had a cure-all for petrification, but knowing the specific kind and how it happened would be useful at least and life-saving at most. 

Regulus had almost forgotten that Lockhart was his partner.

“I am _begging_ you, Gilderoy, to let me keep control of this?  This has been my project for years,” he said evenly, and the man just smiled. 

“Of course, Regulus, I’d never take credit for your hard work!  After all, my achievements speak for themselves.” 

Regulus kept his thoughts on _that_ to himself. 

And it had started well enough—he explained his reasoning for the club, the procedure for what they’d be doing, and paired students up.  He stood on a table across from Lockhart to demonstrate Expelliarmus, when the man started in—

“And if an opponent seems too strong, one of the best ways to defeat them is to get their wand away from them! Simply cast, ‘expelliarmus!’” and he attempted to cast it.  Instead, he only managed to fling his own wand to his feet. 

“Thank you, Professor Lockhart, for showing the incorrect technique first,” Regulus said.  He gestured for him to pick up his wand, and returned with the actual spell, sending his wand flying.

“Right, now I want you all to practice with your partners.  In an official duel, you’ll face your opponent and bow before beginning, but in real life, if you’re forced to defend yourself, that’s not going to be the case.  Because we’re all learning, I want you to agree with each other what spells you will and won’t use before starting, and to give yourselves a countdown.  Understood?  Professor Lockhart and I will pass around pairs, so mind your aim and don’t be surprised if I intervene to give corrections or comments.”  After a few minutes of muttering to one another, the students squared up to duel. 

When a snake came out of someone’s wand, Regulus zeroed in on it and rushed, but not before Harry Potter started hissing at it. 

Flashes of a pale face with red eyes came to mind.  But he banished the snake and turned to the one that had summoned it—Draco. 

“Was that one of your agreed upon spells, Mister Potter?” he asked. 

“No,” he said.  “I—what’s wrong?  Why is—” but everyone was quiet and staring.  Regulus remembered all too well how attention felt in a moment it was unwanted, so he shook his head. 

“Back to your duels, everyone.  Ten points, Mister Malfoy, for not following instructions.  Ten, Mister Potter, for handling it.”

A Parselmouth—now he had to add checking the Potter family tree for parselmouths, didn’t he?

* * *

Of course, there was nothing—a year of playing catch-up, trying to find out what was petrifying students, trying to pacify the Ministry alongside the rest of the staff, organizing the Dueling club further, helping with the potion that would save them, everything was just too much. 

And then Lockhart claimed he could save them all, that he knew exactly how to do it. 

“Be my guest, if you think you know what to do, Gilderoy,” said McGonagall. 

And they, assuming he wouldn’t take them seriously, left it at that. 

_Like idiots._ Mere hours later, Lockhart came stumbling into the staff room with Dumbledore’s phoenix, Harry, Ron, and Ginny, all alive if worse for wear.  Regulus sat in on Harry telling them what had happened, that Tom Riddle a.k.a. Voldemort as a student had been possessing Ginny, had tried to kill her to revive himself.  A twelve-year-old had destroyed more horcruxes than him without even knowing what they were.  Regulus was going to have to ask Harry how he got in so he could get those Basilisk fangs. The monster of the Chamber had killed Moaning Myrtle—Myrtle Warren, one of Riddle’s classmates.  One of Hagrid’s classmates.  Apparently, he’d been blamed for the whole thing.  Regulus made a note to send some strongly worded letters to the Ministry about allowing Hagrid to study magic legally again. 

His influence as a Black, he’d find later, was strong enough—Hagrid would be instated as the next Care of Magical Creatures professor, thanks to him. 

Which led to the next questions, as Ginny Weasley had not gotten the diary on his own.  Judging by Albus recounting his suspicions, Lucius was to blame—another reason to watch Draco this year, but another reason to think he might be watched by Lucius.  If the Malfoy was still loyal to Voldemort (which was certainly likely), he had to have been harboring that horcrux since the Dark Lord’s fall. 

Regulus had a new list to start—lining up those that would be most loyal with artifacts that they might have been entrusted with.  Bellatrix came to mind immediately, which meant that he’d have to try to deal with Gringotts. 

A few weeks into his bargaining and piles of paperwork, his owl, Emrys, fluttered in with the Prophet.  He glanced at the headline—he’d probably leaf through it later. 

Regulus could have sworn a dementor had run a finger up his spine as he saw the face screaming across the front page. 

**Notes for the Chapter:**

> Yeah I really felt like Reg had to have this conversation with Draco sooner than later. Bella really shook him up, so he's trying not to lose any more family to Voldemort's cause. This means the next chapters will be all the juicy stuff we've been waiting for!


	8. Black Lion Meets Wolf

**Summary for the Chapter:**

> From the moment Regulus lays eyes on the headline, worst-case scenarios keep running in the back of his mind. Now he has to help the apparently werewolf boyfriend of his brother not become a murderous creature by night, all while school still trudges on.

Sirius had escaped from Azkaban. 

Regulus, still over-cold for it being the middle of the summer, took the newspaper with shaking hands.  His knuckles, he noticed after a moment or two, were turning white from gripping it so hard. He read on. 

Apparently, it had been after reading an article that explained that Harry Potter was attending Hogwarts, and that Sirius was reported as calm as could be during the visit. 

Calm and ordinary, asking for the crossword from the Minister.  That hadn’t been Sirius at all—Regulus would have known it was a trick to look at the article.  Too clever by half, a trait McGonagall had called them both. 

He called Kreacher immediately to the kitchen, telling him the news. 

“If Sirius comes anywhere near here, you are to alert me, understand?  I can’t have him—I won’t have him hurt anyone needlessly.” Kreacher nodded. 

“Yes, Master Regulus.  Kreacher won’t let the traitor inflict harm and will call for you if he crawls his way back here.”

Within the hour, he began receiving more letters.  Narcissa, Andromeda, Dora, Dumbledore, Rita Skeeter, Fudge himself—all wanting the first word. 

Sparks flew from his fireplace, throwing flickering long shadows in contrast with their golden spray. Regulus whirled to face the Floo call—Dumbledore. 

“I’m sure you’ve found out the fruits of Dementors as the only security available to Azkaban,” Dumbledore asked.  “You did visit two Christmases ago, correct?”  And though his skin still felt the chill of knowing that his murderous brother was about and free, his eyes burned with indignation like the coals Dumbledore spoke from (and if that burn meant tears too? Well, he had reason, didn’t he?).

“And I never even _saw_ Sirius.  I’d ended up stopping by Bella and being so disturbed by that wretched place that I left, Albus—I have not seen or heard from my brother since before Voldemort’s fall.  You want me to repeat that under Veritaserum?  Because I will, happily.  I would not _dare—_ ” he cut off with a frustrated scoff. 

“Wouldn’t dare help your brother get away from ‘that wretched place’?” Dumbledore asked, and Regulus could scream. 

“No, not after what he’d done!  I still can’t fathom—Bella made _sense,_ joining them, and I know why I did.  But Sirius . . . I suppose I never understood him as well as I thought,” he said.  “So while I’d love for this to be simple and point you at him, I don’t know where he is, I don’t understand how or why he did what he did.”

“I didn’t think you did—only that your place helping me destroy the horcruxes has been shaky from the beginning, and I wondered if you had another reason for distrusting me, Regulus.  Perhaps you knew more than this old man in the end.”  . . . _What._  

“Excuse me?! I was ready to _die_ for this, Albus!” Regulus shouted.  “I meant to die then and there, and you think I’d help him?  I’m . . . disappointed you had so little trust in me, in the end.  But I suppose it’s what I expected, isn’t it?” He cast aguamenti on the fireplace, extinguishing the call before collapsing back into his chair.

“Merlin,” he groaned.  He’d either cleared his name in Dumbledore’s eyes, or cut off any help he had to get rid of the horcruxes.  Yet again, they’d have to go on the backburner. Except, perhaps, the two he was currently guarding—the locket, and the cup in Bella’s vault that he gain access to after a bit of haggling with goblins over the first few weeks of the summer. 

It felt _immensely_ good to stab the horcruxes through with a basilisk fang, listening to them screech. 

After a few hours of going through the letters that had been dumped on his desk, he began his replies.  Nothing to Skeeter other than essentially a cease and desist, similar ones to other journalists and most of the former Death Eaters inviting him to dinner.  To his family and to the Ministry, he made his position clear. His letters to all of them told the same thing. 

_I have been at Grimmauld Place all summer. I’m willing to prove that I had no idea.  I have only ever visited Azkaban once, and that was two years ago, and I haven’t seen Sirius since I was in school. All of this is news to me, same as the rest of you. I am just as afraid of Sirius as anyone._

And it wasn’t a lie.  Because he knew who Sirius used to be, but he didn’t know anything past their days in Hogwarts.  He knew the brash smirks, the pranks, the puns. He knew the temper— _Merlin_ but his temper had been as sharp as their mother’s.  And when he got angry, he was as ruthless as their father with his spells and with his words.

He updated his wards, checking them over every time he left the house, every time he returned, and every night before he went to bed.  Dumbledore didn’t call again. 

* * *

“It’s fucking ridiculous!” Dora grumbled over her firewhiskey.  “You’re as Dark as a bunny rabbit.  Or a kitten.” Regulus raised his eyebrows and promptly turned into a cat just to meow at her before turning back.  She blanched. 

“I didn’t know you were— _Merlin_ Reg did you spy on students like that?”

“No more than you changed to look like me if I was late to class so you could make fun of Charlie,” he grinned, taking a sip from his own mug.  Luckily, no one in the Three Broomsticks had anything to say about him, too busy with their own meals and drinks. 

He’d met with Tonks to discuss the Ministry’s position on him potentially helping Sirius—most who knew him personally didn’t think so, though some older aurors were bitter about him being a former Death Eater and were suspicious all the same.

“I _was_ Dark, Dora, and you’d be smart to remember that. Not everyone is trustworthy if they’ve been at your side.” She rolled her eyes. 

“Don’t try and convince me; I’ve seen you after grading exams.  And after Dad’s attempt at Christmas dinner.”  Regulus snorted, remembering Ted’s dumping an entire chocolate cake in his wife’s lap when attempting to set it on the table.

* * *

After they finished and Dora went home for the night, Regulus went to the castle.  Dumbledore wanted to meet him personally for something.  He’d been stewing in fear and anger the whole time, not sure if he was going to have an ally at the end of this—or a job, for that matter. 

“Gummy rats,” he said all the same, entering the office two minutes early. 

The headmaster’s face was hard to read as he gestured for Regulus to sit.  The office was dim with the evening sun setting, filtering only a bit of golden light through the window.

“I must begin with an apology,” he said, leaning back in his chair.  “My paranoia wasn’t unfounded—I’ve broken my own loyalties before for the sake of the greater good.  But it _was_ unfair.  You are not the kind of man to risk your life for a mere ruse.” Regulus huffed. 

“To be perfectly honest, Albus, I expected the distrust from all corners once I got the news.  I’m a paranoid man, too—Alastor Moody would be proud of you and I on that matter.”  Dumbledore chuckled. 

“Perhaps so.  Now, Regulus, I’ve called you here to beg your forgiveness—and a favor.  On behalf of our new Defense professor.”  Regulus raised his eyebrows—what loon had Dumbledore managed to find this time?  And what did he need Regulus for? 

“I’ve already asked Pomona to plant an excess of aconite for the year in the gardens, as well as any other necessary ingredients, but I wouldn’t trust anyone but you to keep this both secret and well-taken-care-of.  You see, our new Defense professor is a werewolf.” 

Oh, so a homicidal loon rather than a stupid one, fantastic. 

“Are you daft?!” Regulus blurted.  “A _werewolf_?!  I can brew Wolfsbane, yes, I’m sure, but the precautions—how on _earth_ would a werewolf even want to—” He shook his head.

“I’m sure there’s more?”

“I assure you, Regulus, he is not only qualified, but overly so.  He is a good young man—one that simply has a condition he didn’t ask for.  He was bitten when he was a child.  The Wolfsbane potion will simply make things easier for him than it had been in his years as a student.”  Regulus stared, trying to comprehend—Dumbledore had called him a young man.  This professor could very well have gone to school with him.

“And who is it that I’ll be brewing potions and substituting for once a month?”

“Remus Lupin.” 

_What the hell._ Regulus thought back on the mousy boy that had been as close to Sirius, if not closer, than Potter. In fact, they’d been inseparable—if James was practically Sirius’s brother, then Lupin was practically his boyfriend, always attached at the hip.  They might have been, if Sirius wasn’t such a flirt. 

(Then again, if Sirius had kept _this_ to himself, perhaps it wasn’t such a stretch.)

Lupin was sick so often, but whip-smart and able to get high marks all the same.  Always tired, for reasons Regulus was only now beginning to understand. 

How strange it was that up until now, he had never learned Lupin’s secret—with all the betrayal Sirius had committed, it was a wonder he hadn’t ruined the man, too, when he’d had the chance.  What loyalties did he _really_ have?  Was Lupin even worth trusting?

Remus Lupin, who’d been the kindest of their little group to him, who would grimace in sympathy as Sirius would deliberately change paths to avoid Regulus in the hall after he’d run away.  Who’d munch on chocolate a little too loudly in the library as he studied with Evans and Kingsley.  Oh, they’d never been friends, but Regulus had thought he’d known Lupin well enough. 

He thought he’d known Sirius, too, so more fool him. 

 “Dammit, Albus,” he sighed, slumping in his seat, “I’ll do it.  I’ll substitute when he can’t teach, I’ll brew the potion, and I’ll keep the secret.”  Dumbledore inclined his head, eyes twinkling softly against the candlelight. 

“Thank you, Regulus.”

* * *

For all Lupin’s secret had changed perspectives, it certainly hadn’t changed much else when Regulus caught him in the Leaky Cauldron—he looked far older than he was, but he was plenty recognizable.  He’d always seemed older than he was, anyway, but it seemed that the years and the deaths had only accelerated the process. 

It was entirely chance, but Regulus couldn’t help himself. 

“Lupin,” he said, sliding into the other chair at his table.  The man looked up from his coffee and blinked owlishly.  A look of shock and fear slid on and off of his face quickly—he’d clearly mistaken Regulus for someone else.  Black family traits, and all that.

“Regulus,” he said tentatively.  “You look well.”  Regulus snorted. 

“I certainly don’t _feel_ it, but thank you all the same.  You seem—tired.”  Lupin gave him a wan smile. 

“I suppose that’s the case.  Lots of changes coming up—and I suppose the news has had me on edge.”  Ah.  Right.  Gryffindors didn’t tactfully back out of explosive topics.  They rushed in. 

“I received no less than thirteen letters within the hour that it came about,” Regulus nodded, “And a floo call from Dumbledore, which was much less pleasant than I would have liked.”  Lupin seemed to relax a moment. 

“He sent for me, too.  I think he probably checked every close living contact he could—though most of us are dead or near as we can be.”  Lupin grimaced. 

“I never understood him, I suppose.”  Regulus blinked. 

“That’s exactly what I felt about the whole thing, too.  Say, uh, Dumbledore told me about—about you.  I’ll be brewing a monthly potion to handle it.  Is there anything I should know?” The werewolf stiffened as if he needed to leave, but his cup was still near-full and steaming.  He shook his head, and the next few moments were silent.  _Well, this could likely not get more awkward._  He’d just have to escape so Lupin could enjoy his cup.

“Well, I do have an engagement to attend to, so I’m afraid I’ve got to leave,” Regulus said, nodding curtly, “But it was good to see you, Remus.”  He didn’t look the man in the eyes as he hurried out, heart pounding.  He’d have to check the lunar calendar, wouldn’t he?  He’d have to line it up and schedule his brewing, and the Dueling club, and discuss curriculum with Lupin— _Merlin,_ but this was going to be a terrible year.

* * *

The fact that this was going to be a terrible year was compounded by the fact that, apparently, dementors had been set loose on campus in order to catch Sirius.  His first week before classes were a nightmare. 

Regulus, being a reasonable and concerned person, wrote a letter to the Ministry with a few curses and all right it was a Howler because clearly soul-sucking monsters were the solution when they couldn’t keep Sirius in prison in the first place.  This was a _school_ , not a prison, and Regulus was going to throw his goddamn weight around.

There were only so many things he could do at once. 

“We had an assigned curse breaker to protect the Mirror of Erised before Albus even _put_ the stone in it—I would think the Ministry can spare a single auror or guard,” he’d said when Minerva had taken him aside to ask him what the hell he’d been thinking. 

He’d been thinking of burning from the inside out, of cold hands dragging him underwater, of _not enough air_ , and that he didn’t particularly care for those kinds of horrors being dredged up again among the rest of the problems he already had to deal with. 

His foray into using his name to get things wasn’t enough to stop dementors from being a problem on the Hogwarts Express, but they were enough to cut their presence down and to assign some aurors in rotation to the school instead.    

As Dumbledore addressed the students, Regulus met no one’s eyes.  A warning about his brother wasn’t going to exactly take him out of the spotlight—he was unlucky enough to share a name with Sirius, unlike Lupin, who for all intents and purposes should have been under more scrutiny than him. 

But the Ministry had capitulated, and he was able to keep a close eye on Lupin, so there were some victories after all. 

* * *

“Professor Black,” Harry asked, hovering in the door of the classroom.  Ah, he should have prepared for this. 

“Hello, Harry.  I imagine you have questions.”  He was only thirteen—nearly the same age Regulus was when Sirius left Grimmauld for the Potters. 

“Do you know Sirius Black?”

Regulus barely kept in his bitter laughter. 

“He’s my older brother, though whether I know him is hard for me to say.”  Harry’s eyes widened as he processed it, lips pursed. 

“Then . . . why is he after me?” 

If only Regulus knew.  He sighed. 

* * *

“Professor Hagrid,” sighed Regulus, “You should take points from Draco for not following instructions.  It’s his own fault; I heard accounts from multiple students.  I’ll see to it that he doesn’t try to use Lucius against you.”  Hagrid blinked, frowning suspiciously. 

“That’s not exactly the right thing, though, innit?  He _did_ get hurt in my class, y’know.”  Regulus shook his head. 

“And if he’d spilled a boiling potion on his arm, I would have taken points, too.  From what I hear, you’re a good professor.  I would hate for my spoiled cousin to ruin that—and for him not to learn his lesson about listening to safety instructions.” 

With a dazed smile, as if he hadn’t expected Regulus to take his side, Hagrid nodded and turned to Draco, who was whining in his hospital bed. 

“And that’ll be ten points from Slytherin, fer not listening,” Hagrid said.  Draco’s eyes widened as he glanced between Madame Pomfrey, Regulus, and Hagrid, as if he expected someone to laugh.  Regulus just shook his head. 

The kid needed to learn.  A letter to Narcissa would suffice. 

* * *

Sirius sightings were pointing him towards Hogwarts. 

Regulus coped with this mostly by ignoring the fact and drowning himself in a combination of his actual responsibilities and wine.

His first attempt at Wolfsbane was successful, and Lupin had been civil about sharing lesson plans, so his weekends were either grading or trying to think of a location for the Diadem—which was of course, a terribly difficult venture, considering no one had seen it in living memory. 

Luckily enough, boggarts were easy to deal with, and when it was the Hufflepuff-Slytherin class, Regulus was able to teach it without accidentally having the boggart turn into Voldemort or worse in front of thirteen-year-olds.  The older years were working in theory for a week before tackling the next subject, so he had them reviewing. 

Lupin was back to teach Gryffindors and Ravenclaws the boggart lesson, and Regulus was quite certain that students were giggling at him specifically because of Lupin. 

He’d ask, but that would just make it worse. 

* * *

Lupin had basically recovered from his second full moon—he always seemed much less agitated during new moons, and that was around Halloween at that point. 

But unfortunately for everyone involved, Sirius had some-fucking-how _snuck_ into Hogwarts without the dementors or the aurors or anyone at all noticing, gotten up to the Gryffindor entrance, and slashed the Fat Lady’s portrait in an attempt to get in.  Regulus didn’t know a strong enough invisibility cloak or spell that would last long enough for him to get on the grounds, much less all the way up to Gryffindor tower.  After settling down the Fat Lady and placing Sir Cadogan in charge of the dorms, Regulus made his way out of the castle to breathe.  He found Lupin in the Clock Tower after everyone had settled for the night in the Great Hall, aurors at the ready. 

Lupin was leaning against a window ledge, and the amber glow of a cigarette lit up his face. 

“Black,” he said quietly.  “I am _beyond_ not in the mood for your face right now.”

“No one asked you to look,” Regulus snapped before scrubbing his face with his palm.  He joined him at the window, looking down on the dark castle. Silently, he held out a hand and Remus handed him another from the box. 

He inhaled, and the puff that followed smelled exactly like Sirius. 

“I’m surprised they don’t have aurors trailing us,” Regulus said dryly. “Sirius’s brother and his last living friend.”

“They trust Dumbledore,” Remus shrugged. “Merlin knows why, with both of us here.  Are you here to question me?” A month and a half ago, he’d have said yes. 

A month and a half ago, he hadn’t watched the relief in the man’s eyes as he drank the bitter Wolfsbane.  A month ago, he hadn’t seen students excited to use new techniques from Defense in the dueling club.  Three weeks ago, he hadn’t heard students laugh about defeating their boggarts, snickering about something Regulus apparently would never know. 

“No.  I’m doing the same thing you are—getting some air and wondering what the hell happened.”  Remus chuckled. 

“Good thing I’m not the only one.  Last I saw Sirius in person, we’d kissed goodbye, and he told me not to get killed.”  Regulus coughed, spluttering. 

“What? I—that is—” Remus laughed, a dry, low thing. 

“We’d been discreet, for all our friends called us hopeless lovebirds.  And I was doing recon missions among the packs up in Norway. I got home to the news that he’d killed Peter and betrayed us all.”  Well, that sounded familiar.  Regulus hummed. 

“I remember waking up to all that.  It was like a nightmare.”  Remus grimaced and exhaled another breath of smoke. 

“And I still keep these because of him,” he said quietly, “After everything, I miss him—who I thought he was—and he never looked at me like I was a freak.  I suppose I should have looked closer,” he said.  Regulus shook his head. 

“We all thought he was the person we saw.  You can’t be blamed any more than me.”  Remus laughed again, distressed this time. 

“He’s out there, and I’m not supposed to feel guilty?  That I loved a man who was a murderer?  What kind of a monster—hah,” he cut off. 

“He was supposed to be the good one,” Regulus murmured.  “I hate that he isn’t.  I despise him more now than I ever did when he ran off.  I don’t want him to get the Kiss, all the same.”  Remus nodded, distantly glancing across the castle and lake. 

“I don’t want them to kill what’s left of the man I loved,” he agreed, “if there’s any of him left.  I want to be the one to end it, given the chance.” 

“Only if I can help,” Regulus muttered. A smile twitched across Remus’s face, more wolfish than Regulus had ever seen. 

**Notes for the Chapter:**

> Timeline-wise, this is "Owl Post" to the beginning of "Grim Defeat" in Prisoner of Azkaban. 
> 
> Regulus and Remus reminiscing - talk about alliteration! This was a fun chapter, and I'm crossing my fingers that I will, indeed, get this done sometime before school starts (for me, Aug 15), but it's likely that I'll probably only get one more chapter out before then. Also, might I just say that xenophobic wizards would have a field day knowing Dumbledore hired a half-giant and a werewolf in the same year? Oh, right, they did. Also, I will probably not include the actual letter Regulus sent to Narcissa about Draco, but I can assure you it's something along the lines of "control your idiot husband's influence on your son or I will do it myself via painful curses"
> 
> What did you like, dislike? I admit, irl I hate cigarettes with a passion but it fits that Sirius probably smelled like smoke. We could even cheat and say they're wizarding ones that smell like incense and don't, you know, cause cancer. No excuses for Regulus's weekend day drinking habits though.
> 
> Comments give me motivation and validation, even if it's a keyboard smash- I will interpret it somehow!   
> Thanks for reading!


	9. Regulus' Dealings with Gryffindors, ca. 1994

**Summary for the Chapter:**

> Between befriending Remus and meeting quietly with Neville, it seems that Gryffindor house wants a lot more to do with Regulus than his own this year.

It was poison and fire and cold, grimy hands whenever Regulus encountered the dementors looming on the outskirts of the grounds.  He gritted his teeth and cast a meager Patronus to resist them, but little could really be done when he didn’t have something corporeal to counter them with.

Remus became a tentative friend, willing to sit with him for drinks or to help at dueling club meetings.  Regulus knew it must have been difficult to deal with him, but as he learned, Remus was as bitter as he was, and harsher besides.  He would have been sure that the aurors would have been suspicious over their friendship, but whatever made them decide against tailing them closely, Regulus was grateful.

They didn’t do any reminiscing, because any memories they had together brought them around to Sirius.  But they were comfortable, familiar, past the awkward stage of figuring out whether the other could stand their company for a long time. 

Unfortunately, though, Remus wasn’t available every Hogsmeade weekend, spending his time catching up or recovering from a full moon.  So this time, when Regulus was antsy to be out of the castle, he joined other professors at the Three Broomsticks. 

“Have there been any more sightings?” asked Madame Rosmerta, taking their orders.  Sprout shook her head, and that prompted Rosmerta to huff and go on a nostalgic tirade. 

“Of all the people to go over to the Dark Side, Sirius Black was the last I’d have thought … I mean, I remember him when he was a boy at Hogwarts. If you’d told me what he was going to become, I’d have said you’d had too much mead.”

_Yes, a lot of people would have said that.  In fact, a lot of people had, hadn’t they?_

“I would have laughed,” Regulus nodded, frowning. 

“You’d have thought Black and Potter were brothers!” chimed in Professor Flitwick. “Inseparable!” He then looked at Regulus and gave him an apologetic grimace. 

“More than I ever was,” he griped.  “Which is why the whole thing never made sense.  He loved the Potters more than the Blacks.  I’m sure if he’d thought about it long enough, he would have changed his name to Sirius Potter.  So what on earth possessed him to throw it away?”

“We’ll never know, I suppose,” McGonagall sipped her drink.  “I wouldn’t be able to bear visiting Azkaban for that conversation.” 

“Me neither.  I’m surprised he hasn’t made a public move, with both Remus and I here.  You’d think he’d appeal to a former friend or potential ally, make a big scene of it.” McGonagall snorted, bitter. 

“The showboat.  He and the others—dear friends, all of them, to a point.  It makes me regret how hard I was on Peter,” she said.  Regulus shook his head. 

“Not to speak ill of the dead, Professor, but you gave him what he deserved at the time.  His life would have been worse if you hadn’t pushed him—maybe even shorter than it was,” he said.  Pettigrew had been the kind of man he wouldn’t expect to be Gryffindor.  But then, he’d thought the same of Ben Copper or Neville Longbottom at times, and there were other ways of showing bravery or honor. 

As they trailed off to other topics—global quidditch, problem students, and the like—Regulus nursed his Firewhiskey.  He felt . . . watched.  Unsettled.  _No one could believe that Sirius would do it, huh?_

Something felt dreadfully wrong about that statement.  Perhaps because—if his brother was able to defy expectations, who else might have slipped past his notice?  A small voice in the back of his head also piped up, one he immediately squashed. 

_~~What if he~~ _ ~~didn’t _do it?_~~

* * *

Remus needed his potion just before break started.

The man looked ragged as Regulus had seen him yet—he couldn’t imagine having to go through holidays in that kind of state alone.  He told him so, but only received a wry grin and a shrug in return.  Remus refused any and all attempts to get him to come over for the holidays (the only reason that Regulus relented, in the end, was because perhaps the man could do without a Black family event on a Christmas when a particular Black was both his first main connection to them and also the most painful topic of the year. 

Another holiday, then, if he survived the Defense professor jinx. 

Kreacher was looking well—the house and the elf matched in that regard, and that assured Regulus that at least one constant would remain: his home was here, safeguarded against the outside. The elf, for his old age, seemed pretty spirited for the holidays—with preparations for visitors well in hand, Kreacher was downright jolly. 

Narcissa, Draco, and Lucius arrived first, just under an hour early.  Draco was clearly still bitter with him over the whole hippogriff incident, because he refused to talk more than absolutely necessary. 

When Andromeda, Dora, and Ted entered through the fireplace, Lucius started clearly sneering at them.  Regulus raised his eyebrows, but didn’t make a comment out loud—it was poor form, and the man knew it, so he’d leave it to Narcissa to scold him later. After dinner, they exchanged gifts. 

Regulus presented Draco with a set of practice snitches like the ones he’d gotten when he joined the Quidditch team in school—a set of five silver ones with specified enchantments on each for the sake of difficulty and technique. Narcissa gave him a safe that he could link to a portion of the Black Family Vaults to access specific artifacts or amounts of money if he wanted.  Dora gave Lucius a book of peacock-related lore, which was thankfully not laced with a Zonko’s product waiting to turn his hair pink. 

And Regulus received a letter, asking if he’d sent Harry Potter a firebolt, and if not, to please access his vault to see if there was any tampering.  There hadn’t, because Sirius was a dramatic dipshit, and _that_ clearly hadn’t changed. 

* * *

“Remus.”  Regulus frowned at him, gesturing to the parchment in his hand.  He didn’t particularly care that the thing had insulted him, but it was important somehow.  A Zonko’s deflection might have satisfied Harry, but Regulus?

“Yes?”

“What is that thing?”

_Mr. Prongs would like to invite you to jump into a pool of flobberworms._

_Mr. Wormtail believes you’ve got quite a big nose to be going through others’ business._

_Mr. Moony prefers to not deal with buffoons, thank you very much._

_Mr. Padfoot would like to express his astonishment that Professor Black got a hand on this, the little git. Use it well or toss it to someone who will._

Something about the names was familiar; not to mention the little git comment sounding pretty similar to comments he’d often heard himself at home.  Remus hesitated for half a moment too long. Regulus shook his head, disappointed. 

“I’d think you’d trust me by _now_ , Remus.” It wasn’t that, of course, but it was enough to make him deflate. 

“The Marauders,” he said.  “It was ours.  Me, Moony, Peter as Wormtail, James as Prongs, and Sirius as Padfoot.  We made the map with a passcode—‘I solemnly swear that I am up to no good’—and made it wipe itself with ‘Mischief Managed’.  A lot of charm work, could track people throughout the castle.  Though he no doubt remembers the secret passages, the passwords have changed, and he can’t know the routes of the auror or dementor guards.  That’s one saving grace, I suppose. I have no idea how Harry got his hands on it.”  Regulus raised a brow. 

“You’re talking to a man that has been teaching the Weasley twins since their first year.  Where do you _think_ he got it?  They probably idolized you lot for the thing,” he said, shaking his head.  Remus huffed, smiling. 

“Fair point. They’d never believe it.”

* * *

 

Regulus was going to kill his brother; of that he was certain—if only to get rid of the Ministry-Azkaban rotation at school.  In addition to dementors and Aurors, they’d deemed it necessary to send politicians. Fudge frequented the grounds, fretting about security measures, and there were rumors yet again that they might have to close the school.  Students were glaring at Harry, ever-half-aware that Black was targeting him.  No doubt Sybil’s predictions had made _that_ deduction all the worse.  As it was, he had one of Fudge’s busybodies following him around from tutoring sessions to Dueling Club, disapproving of practical methods vocally like he actually cared about her opinion. 

“Hm—” she’d clear her throat in the middle of a tutoring session and hover right behind him.  The first time, he’d allowed her to intervene, but all she’d spouted was regulations and so-called corrections to his teaching methods. 

This lasted through the first half of the spring semester, before she returned to the Ministry and a mousier woman took her place. 

(It was a good thing, too, because the woman almost made him _want_ to have Sirius show up and go on a murdering spree, so no one would blame him for an evident homicide.  He knew how to blame his brother on things, after all.) 

* * *

 

Neville came to him after class, in a bout of unexpected boldness.  Apparently, whatever Remus had done with the third years had been enough that Neville no longer completely cowered during his entire class.  This was the first time he’d voluntarily approached, however. 

“Professor Black?” he asked.  “I was wondering . . . about this weeks’ assignment.  The wormwood properties essay—could I just check to see if I’m going about it the right way?” he thrusted a piece of parchment at him.  Regulus raised his eyebrows, but he nodded all the same. 

“Of course.  Mind sitting with me for a moment, to take a look?”  Whatever bravado he’d had, he no doubt used up on the first few moments, because he sat down quickly and averted his eyes. 

Regulus read the paper carefully—it looked a bit like it was leaning towards the Herbology components of the plant, rather than how it pertained to potions specifically.  Luckily enough, the two topics overlapped, so it wasn’t too much of a stretch to get a good grade with some edits. 

“Do you like Herbology, Mr. Longbottom?  This essay is more appropriate for Professor Sprout’s class, but you’ve got a lot of the elements I’m looking for.”  The boy nodded. 

“I prefer taking care of plants. It’s quiet, slow work, and it’s hard for me to mess up.  Or at least easier to fix mistakes over time,” he said. “It doesn’t take much magic.” _. . . oh._ If he remembered the boy’s family well at all, then he knew what they did to check for Squibs.  After Frank and Alice—it was no wonder.

“Neither does potions, ultimately. It’s all about following directions, Neville. Here,” Regulus summoned a quill and some blue ink.  “I’ll make some marks for the changes you can make to get a near-perfect score.”  He’d keep an eye, take extra care—Neville Longbottom could do well as a potion maker, and with control of the whole process for the majority of his ingredients, he could succeed even further. 

While Regulus wrote down some corrections, Neville fidgeted with his wand. 

“I understand that in Potions, there’s no chance to undo damage.  That if there are consequences, they’re more immediate—and that’s always more frustrating.  Professor Lupin, when he was in school, was notorious for being terrible in Potions.”  Neville blinked upwards at him. 

“Really?”  Regulus nodded. 

“Slughorn always had him partnered up with one of his star pupils—both to challenge her and to help him, I think—so don’t think because you aren’t successful at one thing means the end of the world.  I still want you to try your best and get better, but you don’t have to be perfect.”  Regulus smiled gently and handed Neville the edited paper, with notes on what books to reference and other topics to lean towards.

“There.  Thank you for stopping in—and let your classmates know that they’re welcome to do the same?  All the Gryffindors and Hufflepuffs are afraid of me, it seems,” he chuckled.  And it was mostly true, because of the younger students, those houses tended to cower in his class longer than others. 

Neville nodded vigorously, muttered a quick goodbye, and rushed out of the room. 

_Well.  Progress is progress, no matter how small._

**Notes for the Chapter:**

> Yeah, this is probably the second-to-last chapter, and the last one will be a doozy, but I felt I had to post it as it is now or I'd never move on to the major finale, which is why we're all dealing with this premise to begin with. It's going to be a while, but it's not on hiatus - it's just a lot to write.  
> Hope y'all are doing well! Feel free to comment - that gives me more motivation to finish this!


	10. Cat meets Dog and Rat

**Summary for the Chapter:**

> When Regulus can't find Remus to give him his potion, he certainly doesn't expect to find the names he does on the Marauders' Map. Time is ticking, and the danger could be coming from more sides than Regulus had thought - he just needs a chance to step in.

Lupin was nowhere to be found.  Perhaps he’d finally given in to self-destructive tendencies and locked himself away in his office, upset by Dementors or Sirius or exams.  Any of the options seemed plausible at this point.

He wasn’t particularly surprised—in fact, he could relate to the idea of locking himself in his office, come exam time.  The past few weeks leading up to exams had had every teacher and student alike agitated, so he probably hadn’t even noticed that his sickness was coming on when _everyone_ was in essentially the same state.  Other positions probably left him alone to dwell on it. 

Far be it from Regulus to let someone wallow in self-pity or nap away a migraine if they needed to for a bit, but the image of his friend in the aftermath of tearing apart his office or bedroom—it made something in his ribs burn.  He was going to have to see if he could create a more effective Wolfsbane, maybe one that counteracted the transformation entirely.  _Yet another project to put on the growing list_ , he supposed, but one he was more than willing to do.

But Regulus didn’t find the werewolf in the Great Hall at dinnertime, so he had to go hunt him down.

_“Dammit,_ Remus,” Regulus grumbled, stoppering the Wolfsbane to begin his search.  He cursed to himself the whole way to Remus’s office, only to find it empty—a familiar piece of parchment laid out on the desk.  Regulus frowned.  Well, at least he could find him easily now. 

“I solemnly swear that I am up to no good,” he said, pointing his wand at it.  He scanned for—there!

Remus Lupin, trailing closely behind—Sirius Black, _bloody fuck_ , Peter Pettigrew, _what_ _the_ _hell?!_ , Hermione Granger, Harry Potter, and Ronald Weasley . . . _why am I even surprised?_   All of them were heading for the Shrieking Shack. 

Immediately his veins turned to ice, and in need of confirmation, he scanned the map again. 

Definitely not a trick, or a very well-crafted, cruel one indeed. 

Regulus frowned and tapped his wand on the shack, to find the entrance—a knot on the Whomping Willow opened a tunnel up, huh?  His mind was racing.  Sirius, Remus, the children—and Peter, who was a dead man.  Regulus pocketed the map before sprinting away to the Whomping Willow.  It was a good thing, at least, that he had time to think on the way. 

_If Sirius didn’t kill Peter, then the witnesses might have been wrong.  If Peter was hiding, alive all these years—he would have been a hero, if he’d stayed._

_But with Peter as a living witness, they’d have the ability to check facts at Sirius’s trial, and—_

_Did Sirius even have a trial?_ Those were dramatic sorts of things the Prophet loved to gush about in the aftermath, and yet he didn’t remember anyone ever telling him about it after all this time.  _Bloody buggering fuck_. 

Or maybe he and Peter had _both_ killed the muggles, and maybe Lupin and the children were about to face off against two killers.  Whatever the fuck it was, he certainly wasn’t going to waste time parsing out his guesses. 

He raced to the Willow, tossing a rock with Seeker accuracy right at the knot and hurrying through.  There were too many what-ifs, of course.  He had to listen, disarm, and protect the children.  Then he could deal with Peter and Sirius—and Remus, if he got caught up too much.  Unfortunately, his calculations in his head didn’t match his speech as he trudged through the tunnel, muttering curse upon curse that would make the most grizzled criminal flush.

He finally made it to the house and already heard shouting.  The floorboards creaked under him as he moved, and he switched quickly to cat form to keep from being announced prematurely.  He tracked the sound upstairs until—

“Hermione, listen to me, please! I can explain—” Remus said

“I trusted you!” Harry shouted.  “And all this time you’ve been his friend!”

“You’re wrong,” Remus was quieter, and the struggling muffled part of it for a moment.

“NO!” Granger shrieked, cutting through the noise.  “Harry, don’t trust him, he’s been helping Black get into the castle, he wants you dead too— _he’s a werewolf!”_ Oh, clever indeed. 

“Not at all up to your usual standard, Miss Granger.  One out of three,” he said.  Regulus held in a snort.  _Not the time, Remus_.  He heard a half-coughed chuckle as Remus continued. 

“I can assure you I haven’t been helping Sirius, and I haven’t been his friend in twelve years.  But that was wrong of me.  We were all wrong.”  Breath caught in Regulus’s chest because _yes yes please I knew it_ his tiny, big-brother-worshipping-self squealed inside. 

_Damn_ him and his bleeding heart.  Damn the little brother in him, wanting to believe—he smothered it.  He didn’t open the door yet.  Lupin was continuing.  Regulus figured he wouldn’t endanger students over a hunch.

“I _am_ a werewolf.  Dumbledore’s known since the beginning, since I’ve been a werewolf most of my life, including my years as a student here.  The staff all knows; Professor Black has been brewing me a Wolfsbane potion every full moon so that I can continue to teach without harming anyone.”

“Professor Black?” Sirius rasped. 

“Your little brother,” Remus said dryly.  “He’s the Potions Master.  A good thing too; it nearly went to Snape.  I would have lost my mind.”  Sirius chuckled, dry and throaty. 

“The Potions Master?  Did he pull a Binns?  Last I recall, Regulus was dead, Remus.” 

“He betrayed Lord Voldemort and paid for it,” Remus said, “It took him some time to get back into the world, but you were already in Azkaban by the time he started teaching.  He’s been at it for some years, and he’s been a good friend to me this year.”  There was a beat of silence. Sirius made a low humming sound. 

“Professor Black, betrayer of the Dark Lord?  That’s . . . Damn, Reggie.”

“Reggie?!” Hermione sounded downright offended on his behalf.  He’d have to award her points at the first opportunity.  _Reggie, honestly_.  That couldn’t stand.

“Really, Sirius?  You haven’t called me that since I was fourteen,” Regulus drawled, making his presence known as he opened the door, wand out. 

“Professor!” the children cried.  Ron was sprawled backwards on a bed, favoring one leg over another.  Regulus frowned—what had Sirius done?  He didn’t have a wand of his own. 

“Ah, Regulus, would you mind holding off on your threats from the earlier in the term?” Remus asked.  “There’s some new information.” Regulus snorted.  Yes, Peter Pettigrew being alive was _new information_ , of course. 

“You’ll have a lot to explain to get through that,” he said dryly.  “And before that, you’d better take your potion.  Remember?”  Remus paled as Regulus held out the vial. 

“Dammit, Moons,” said Sirius fondly, “Never remember to take care of yourself, do you?”  _Moons?! . . . how did I not realize they were together? Honestly._   He handed Remus the potion, who drank it with a grimace. 

“Since I’m probably the only one with a damn level head around here, everyone, give me your wands a moment. I’m not handing my wand over,” Regulus said dryly, “So if anyone tries anything, stunners are flying.” Remus nodded, though Sirius tensed as his protection was taken from him. 

The children visibly relaxed, however. 

“I have reason to believe you’re not a murderer, Sirius. We’re all going to be calm and rational as long as we can stand it, and you’re going to provide an explanation that’ll satisfy Remus, myself, and the children, and _then_ we can go about our business.  If you fail to do that, I’ll handle you myself.”  Sirius blinked owlishly. 

“Uh . . . all right?  How’d you even get here, Reg?”

“Borrowed something of Lupin’s,” he said. Remus nodded. 

“I showed him the Marauder’s Map, Sirius – that’s how I knew to come out here.  I saw the group heading towards the Shack and came as fast as I could.”

“You know about the Map?” Harry asked.  Remus grinned. 

“I helped make it. I’m Moony.  And that’s Padfoot right there.  Your dad was Prongs.”  And then Remus launched into the tale of the three boys finding out he was a werewolf and becoming illegal ani-fucking-magi.  As _fourth years._ Because apparently, they were just that damned reckless and impressive. And if rumors of a Grim hanging around the grounds were anything to go by—

“Wait, don’t tell me.  You’re a big, black dog,” sighed Regulus.  Sirius barked a laugh. 

“What was your first clue?”

Regulus transformed back and forth briefly, and his older brother stared before a manic grin grew on his face. 

“That’s _brilliant,_ Reg—”

“And irrelevant.  Why aren’t we all arresting you immediately?” he asked. 

“Peter Pettigrew was a rat animagus—Wormtail, we called him.  The next part I can only guess—Sirius?”  His gaunt brother’s face broke into a grimace. 

“The Potters had a Fidelius charm on Godric’s Hollow.  I was the obvious choice.  But . . . we were all suspicious of people.  Of Remus, since he was going on missions to spy on werewolves.  I was worried he’d fallen in with them, since he always had a hard time fitting in—and I had a weakness when it came to him, so I didn’t want to be in that position if I didn’t have to be—but the point was, we thought no one would suspect Peter.  So he became the Secret Keeper and went straight to Voldemort.”  Sirius looked apologetically at Remus during his explanation, but Remus only smiled wanly at him, understanding. Regulus sucked in a sharp breath. 

“There _was_ a spy.  I’d wondered how the Dark Lord had been able to predict the Order’s movements.  I’d assumed it was you, when I’d gotten the news.”

“And when I’d found out that my clever decision to pick Peter killed them, I was on a warpath,” Sirius said.  “I would have killed him, sure.  It was still war as far as anyone was concerned, and he is a traitor to this day for what he did.  But he blew up the street, turned into a rat, and scurried into the sewers.  All they found of Peter was a finger, right? And that rat is missing a toe?”  Ron’s mouth was gaping open. 

“He’s my _pet_ ,” he said, disbelieving. 

“And he’s been Percy’s, and Charlie’s before him,” murmured Regulus.  “How long has he been alive?  Rats aren’t known for their longevity, Ron, even if they’re well-taken-care-of.  How long have you had him?”

“Since I can remember; I don’t know!  We always had him,” he said, and Hermione’s eyes widened.  Scabbers was squirming wildly in Ron’s hands, but he held the rat tightly, clearly not wanting anyone else to have a crack at him. 

“I looked it up while I was deciding on a pet for school—rats live three years, at most,” she said.  The boy’s brow furrowed. 

“Ron, may I see your rat?  No harm will come to it if it’s really a pet,” Regulus held out his wand, clear with intent.  Ron, holding his pet firmly outwards, nodded.  Regulus muttered the spell, and the rat screeched and scrambled off the bed, growing as he went. 

And there was chubby, bedraggled, buck-toothed Peter Pettigrew.  The children were clearly horrified.  Peter stared up at them, right eye twitching. 

“Remus . . . Sirius . . . my old friends!  And Regulus, it’s been so long—” Ah, the pleasure of appealing to two opposing sides.  Except, for the first time in decades, Regulus and Sirius were on the same side. 

“Don’t you dare,” Sirius croaked. 

“Been a long time coming.  Together?” asked Remus, and _wait_. 

“No one is killing anyone tonight!” Regulus declared.  Harry nodded vigorously.  Peter’s face pulled into a shaking smile. 

“Oh, thank you, Regulus, Harry—” It was pathetic and obvious, sitting here, who had been afraid enough to betray the Potters.  Why had

“This isn’t a favor to you,” Regulus sniffed. 

“I just don’t think my dad would fancy his friends becoming murderers over you.  You’re not worth it,” Harry said, scowling at the simpering man on the floor.  Peter blinked, eyes watery. 

“Ron, Ron, wasn’t I a good pet?”  The redhead made a strangled sort of squeaking noise.

“I let you _sleep_ in _my bed_!” _And nope_.  That was too much.  Regulus very much did _not_ want to think about what other terrible things the man could have gotten up to, and he once again had to be the pragmatic Slytherin in a room full of brash, vengeful Gryffindors.  Remus and Sirius were likely to want revenge, and the kids didn’t need that sort of thing in their experience.

Remus was already striding towards Peter, and so was Sirius, a dark gleam in his eye that made “grim” seem all the more appropriate for what people mistook him as.

“Petrificus Totalus!” Regulus shouted, wand out.  Peter froze and hit the ground with a heavy _thunk_.  Sirius and Remus both looked back up at Regulus, who was tutting at them already. 

What did they expect?  That he was going to hand them their wands for an Avada Kedavra and that would be that? 

Despite his promises with Remus over killing Sirius, that had been a hopeless cause and a mercy all wrapped up in their fucked-up psyches.  Regulus had no such pretty illusions about Peter—objectiveness made that decision a lot easier.  _Why am I the only actual adult in the room?  Scratch that, why am I_ always _the adult in the room?_ Well, it had been that way since Sirius was _actually_ eight, and not just acting like it. Besides, keeping Peter alive had its uses at the moment. 

“We need him alive.  Honestly, if you expect to be proven innocent at all, Sirius, I’d think you’d want evidence.”  Sirius blinked. 

“You believe me?”  Regulus took a look at his bewildered expression and laughed a little. 

How many times this year had he thought, again and again, _I can’t believe Sirius would have done it_? How many times did the pit of his stomach drop, thinking that he didn’t know his brother so well after all?  Doubting himself, underestimating his ability to read people, trusting government officials to do their jobs—what had he been thinking, anyway?

“It makes more sense than you joining the Dark Lord, honestly—but in all honesty, Sirius, why would you attack a thirteen-year-old?  What did you expect to come out of that in a good way?” he gestured to Ron, who noticeably hadn’t gotten up from his sitting position even when everyone else had stood up.  Sirius winced. 

“One of the hazards of being a large dog—large teeth.  Honestly, I was just after Peter.  Sorry about that—”

“Bloody hell, don’t apologize!” Ron blustered.  “If it were me, I don’t think I could have done different.”  A warm, relieved smile bloomed across Sirius’s face. 

“Remus, if you could . . .?” he handed him his wand, and Remus set to work on healing Ron’s leg.  Hermione skirted the room, keeping her distance from Pettigrew before leaning in to hug first Harry, then Ron. 

“I’m so glad we’re all right,” she said, sniffing.  “Why does everything always happen right around exams?” Harry and Ron laughed. 

“It’s likely because of the fact that at least five bad things must always be happening at once to any given person,” suggested Sirius.  Remus groaned. 

“Sirius!  How on earth could you remember that?!”  Sirius shook his head, finally grinning. 

“One of your shining moments, complaining about the OWLs, a bad date, and forgetting your chocolate up in the dorms while you had prefect rounds.  You know I can’t help it, Professor Moony.”  Remus gave him an exasperated glare, but didn’t reprimand him. 

“At least it isn’t puns,” he muttered, and Regulus nodded in solidarity.  How many “are you serious? Why yes, yes I am,” jokes had he endured? 

Too many. Just, just too many.

“I’ll bring the students back,” said Regulus, glancing out the window, anticipating the moon rising.  “And Peter, to the aurors, for questioning.  You two stay here the night, and I’ll sort out what I can until Remus can come back in the morning.  Sirius,” he turned to face him head on.

“It may take some time to clear your name, so you might have to be in hiding a little longer, but—but I promise you, I’m going to make sure you’re a free man as soon as possible. Understand?” As Sirius nodded, Regulus thought, _oh fuck it before I lose my nerve_ , and leaned in to hug his brother.

Sirius stiffened for only a moment before hugging right back. 

“We have a lot to talk about,” Regulus said.  “But for now, you help Remus through the night, and I will get these students to the medical wing.” And Regulus led them out of the Shack and through the tunnels, now unafraid of a time limit since Remus had had his potion. 

Despite his bedraggled, vampire-like appearance, Sirius seemed to soften immensely at the prospect of spending the night with Remus undisturbed.  It was all the sadder—and it made Regulus all the angrier at whoever could have stopped it from happening. 

Fudge, any number of officials, probably Dumbledore again, possibly some retired aurors. Oh, he’d be tearing some new assholes _for sure_ once he got his chance—

Just the thought, as he led the children back to the castle, towing a petrified and levitating Peter Pettigrew as he went, sent him thinking of twelve years with nothing but his visit to Azkaban.  How in hell was Sirius _not_ absolutely, brokenly, raving mad?  He was only thinking about it and was reminded of the crawling, clutching feeling of Inferi or the stony terror of facing Voldemort and lying to his face. A shiver raced up his spine.  

Regulus frowned.  The temperature had dropped some. 

“Professor?” asked Hermione, who was helping to support Ron as he hobbled along.  “I don’t feel so—”

“Dementors,” Harry said, wand out.  Regulus hissed a curse under his breath. 

“All right, we’re going to be a bit quicker.  Our intense emotions have them tracking us like a moth to a flame.  Hermione, what’s your favorite holiday?” he asked, reminding himself as best he could of Christmas Eve, sitting awake by the fire later than normal, the chill from the outside shut away from them. 

But the distraction wasn’t enough.  No less than six black, tattered figures with spindly hands approached, deliberate and unyielding.  They were surrounded, and though Regulus tried to cast a patronus—he’d never been able to— _Merlin,_ the burning potion, the cold and damp of the cave— _you’re going to die here, Regulus, aren’t you?_ He remembered having that same thought before.  It had only been a matter of time—

“ _Expecto Patronum!”_ Harry cried, and a pulse, two, a stag burst from his wand, white and glowing and majestic, cutting through the skeletal figures.  Regulus wasn’t going to waste time. 

“Get to the castle _now,_ ” he called, and they all rushed for the nearest entrance. 

* * *

The commotion attracted a different kind of attention at the door, however—arguably just as unpleasant as the dementors.  Filch was shouting over his shoulder, hobbling towards them. 

“Students out of bed, Black’s here—”

“Shut up,” Regulus snorted.  “It’s me, not my idiot brother.  Now please let us up to wherever the aurors are staying; I’ve got some important evidence to share.”  Filch grumbled, but the shouts _had_ sent the aurors and the Minister, who’d been observing their protective measures towards the end of the term, rushing to them.  McGonagall, Flitwick, Sprout, and Dumbledore accompanied them all. 

“One of Sirius’s murder victims is mysteriously alive, Minister.  Care to share how _that_ came about?” He shoved Peter forward.  “He was potentially hostile, so I petrified him.  I suppose the aurors you brought with you are more than competent in keeping him restrained for questioning?  After all, if he’s alive, what else could be wrong about this case?” Regulus said.  Fudge was paling by the minute.  Oh, there was sweet satisfaction in watching people he didn’t like squirm. 

Minerva was as white as a ghost, mouth open wide. 

“Peter?” she said softly, and the man’s eyes flicked towards her. 

 “I will happily pull him aside,” called Kingsley, who had Mad-Eye and Tonks with him, along with two other aurors he didn’t recognize. 

“The children were endangered by him—he’s an illegal Animagus, a rat, so he was able to sneak in and out without trouble. Be careful,” Regulus said.  Kingsley raised an eyebrow. 

“We’re going to have to question you and the children as witnesses,” he said, “But they can sleep in the hospital wing—I imagine they might need to be looked over after this ordeal.  Are you well, Regulus?”

“Well, considering Harry just saved us from a dementor attack, I’d say I’m just peachy,” he grumbled.  Flitwick and Minerva both turned towards Harry, curious looks on their faces. 

“And just how did you manage that, Mr. Potter?” Minerva asked.  Harry’s face grew red. 

“I, well—Professor Lupin’s been tutoring me on the Patronus.  Because the dementors affected me really badly?” he said.  Regulus shook his head. 

“A corporeal Patronus at the age of thirteen is nothing to be modest about, Mr. Potter,” said Flitwick with a nod of approval. 

Flitwick and Sprout ushered the children to the hospital wing while everyone else gathered in an arithmancy classroom. 

Regulus offered to grab some Veritaserum he had stored away in his office, but Mad-Eye shook his head.  The spare eye twitched between Regulus and Pettigrew—which was probably all the man needed. 

“In that case, I’ll just sit and observe the proceedings, then?” he stared down Pettigrew imperiously.  McGonagall was frowning as her eyes swept across her former student.  As he backed away to sit on a desk, Regulus was pleased to remember that there were two cats for every rat in the room. 

It seemed Wormtail recognized it as well.  Regulus’ lips curled, and he dropped the petrification. 

* * *

In the morning, Regulus had dark circles under his eyes and a terrible temper.  He didn’t take it out on students, per say, but they could tell it was not a day to push him. 

Draco had noticed.

“Professor Black?” he asked tentatively as he entered Regulus’s office during his free period, a time when Regulus had planned on stopping by Grimmauld to pick some things up for Sirius and then nap for the rest of the period. 

“Draco, come in.  What is it?” he asked. 

“Are you all right, Professor?  You and Professor Lupin seem . . . out of sorts today.  And I heard a rumor that there was a dementor attack last night—that Potter and his friends were there.  Are they—?” his voice cracked as he struggled to finish his question. 

“Everyone’s souls are intact, and the Minister had the proper authorities take in a potential criminal last night.  The dementors were taken care of, if only long enough for everyone to get to the castle safely.” The boy’s shoulders slumped, as if he’d been bracing for an impact. 

“Well—I suppose that’s good, then.  Do you know why they affected Potter so strongly?” Draco asked, and Regulus wondered. 

“Harry’s seen quite a bit of tragedy, Draco.  I’m not sure what specifically makes it as bad as it is, but I can assure you it’s likely not something anyone would like to talk about.  Merlin knows _I_ have a hard enough time around the creatures.  It’s over now, at least, and you don’t have to worry about it.”  Draco frowned at that, glancing around Regulus’s office in disarray. 

“I know you’re the professor, the adult here,” Draco said quietly.  “But don’t treat me like I’m dumb, Uncle.  What happened?  You haven’t looked this shaken since the time you visited Aunt Bellatrix.”  Regulus’s eyes shot up to meet Draco’s.  The boy was standing straighter, not tense, but proud.  _Just like Cissy_ , he thought fondly. 

“How did you know I visited her—”

“Mother visits her.  Not often, but some.  They talk.  Did—did they catch Sirius Black last night?” he asked, awe tracing his voice, and Regulus wondered why it was that murderers held such high interest for young boys. 

“We certainly caught someone,” Regulus grumbled.  “Tell me, Draco, can you keep a secret?”  He knew the answer to that one—yes, if he wanted to. 

 “I’m trusting you to not tell a soul until it’s public knowledge,” Regulus qualified, and Draco’s eyes lit up—wanting to prove himself to his uncle?  Of course. 

“I can keep a secret,” he nodded with certainty. 

“Sirius was innocent all along, but framed.  We caught the actual killer, and I’m hiding Sirius until his name’s cleared officially.” Draco’s eyes widened. 

“You’re hiding a fugitive, and you caught a killer, and that’s why Potter, Weasley, and Granger are all in the hospital wing?”  Regulus smiled indulgently as Draco put the pieces together. 

“Yes, but _not a word_ , not to your parents, your friends, or other teachers.  It could mean Sirius’s life if he’s found out too early,” he said. 

Draco nodded.

“You can trust me, Unc—Professor Black,” he said, sheepishly glancing away. 

“Good.  Then don’t freak out if you see a large black dog and cat roaming the castle together,” he said.  “You have a potions exam to study for, Draco—thank you for checking on me.”  A small nod.  Footsteps. 

Regulus sighed in relief.  _Well, naptime will have to wait._ Regulus made his way to the fireplace, tossed the powder in, and stepped through to Grimmauld. 

“Kreacher!” he shouted, “I don’t have much time to explain at the moment, but Sirius is innocent and will be arriving shortly.  I know you two don’t get along very well, so if you’d like to keep to yourself, I’d suggest taking a rest in the attic for a while.”  The elf nodded with a scowl. 

“Kreacher will stay away from the traitor master, yes, he will,” he said.  Regulus shook his head. 

“He didn’t betray the Potters or kill anyone, actually.”  The elf, however, frowned sympathetically. 

“Sirius Black left Master Regulus behind.  Kreacher does not care about blood-traitor Potters or filthy muggles.  Master Sirius betrayed _you_ ,” he said pointedly before hobbling up the stairs.  Regulus stared after him a moment before shaking his head and gathering up the supplies he needed.  Some of Sirius’ old clothes still hung in his closet—Regulus charmed them to get a little larger, then got out some of his robes that he didn’t prefer anyway and enlarged them slightly, too.  Though they were both adults, Sirius was still a lot lankier. 

These would have to do until Sirius could access the vault properly again.  As an afterthought, Regulus summoned some new toiletries to the bathroom, and transfigured the label to say _Dog Shampoo._ He smirked and grabbed the final piece before hurrying back to the Shrieking Shack.  A cat and a dog heading across the campus might look suspicious, but not nearly as much as a wanted criminal.  Sirius bounded around, grinning at Regulus, who did his level best not to outwardly roll his eyes at every ridiculous endeavor.  When they’d arrived, Sirius looked shocked to find a distinct lack of Ancient in the Most Noble and Ancient House that had been their childhood home.  As he wandered the halls, taking in the brighter painting, the newer furniture, Sirius smiled a little manically. 

“Remodelling, Reggie?  I hate to say it, but I like what you’ve done with the place,” he said. 

“Good to know,” Regulus deadpanned, “I always await your approval.  Since I know you’ll be bored to tears while I’m gone, I made sure the shower was stocked, and here—” he thrust his gift into Sirius’s hands.  A two-way mirror, the second of which was in Regulus’ hands at the moment.  Sirius stared at it silently before glancing up. 

“This one was James’.”  Regulus nodded. 

“I figured you’d want that one.  I can stick with a hand-me-down in the meantime.  I’ll keep you updated,” he promised.  Sirius lurched forward to catch Regulus in a hug.  Regulus pretended not to notice the wetness on Sirius’ face. 

“I—thank you, Regulus, and I’m sorry, you know that, right?” Sirius said hoarsely.  Regulus nodded against him, still clutching his shoulders awkwardly, tightly. 

“And the same from me.  We both have our regrets, but now we have a chance, right?” And Sirius looked mournfully hopeful, smiling softly even as the tears refused to stop. 

Another chance for a framed convict and a defected Death Eater—that sounded like a good place to start indeed. 

**Notes for the Chapter:**

> There will be one more chapter after this as a sort of epilogue - and then that'll be a wrap on Professor Black!


End file.
